1 /*
  2  * Copyright (c) 1997, 2024, 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 "compiler/compiler_globals.hpp"
 27 #include "gc/shared/gc_globals.hpp"
 28 #include "logging/log.hpp"
 29 #include "logging/logStream.hpp"
 30 #include "memory/resourceArea.hpp"
 31 #include "memory/universe.hpp"
 32 #include "runtime/java.hpp"
 33 #include "runtime/javaThread.hpp"
 34 #include "runtime/mutexLocker.hpp"
 35 #include "runtime/safepoint.hpp"
 36 #include "runtime/vmThread.hpp"
 37 #include "services/management.hpp"
 38 #include "utilities/vmError.hpp"
 39 
 40 // Mutexes used in the VM (see comment in mutexLocker.hpp):
 41 
 42 Mutex*   Patching_lock                = nullptr;
 43 Mutex*   NMethodState_lock            = nullptr;
 44 Monitor* SystemDictionary_lock        = nullptr;
 45 Mutex*   InvokeMethodTypeTable_lock   = nullptr;
 46 Monitor* InvokeMethodIntrinsicTable_lock = nullptr;
 47 Mutex*   SharedDictionary_lock        = nullptr;
 48 Monitor* ClassInitError_lock          = nullptr;
 49 Mutex*   Module_lock                  = nullptr;
 50 Mutex*   CompiledIC_lock              = nullptr;
 51 Mutex*   VMStatistic_lock             = nullptr;
 52 Mutex*   JmethodIdCreation_lock       = nullptr;
 53 Mutex*   JfieldIdCreation_lock        = nullptr;
 54 Monitor* JNICritical_lock             = nullptr;
 55 Mutex*   JvmtiThreadState_lock        = nullptr;
 56 Monitor* EscapeBarrier_lock           = nullptr;
 57 Monitor* JvmtiVTMSTransition_lock     = nullptr;
 58 Monitor* Heap_lock                    = nullptr;
 59 #ifdef INCLUDE_PARALLELGC
 60 Mutex*   PSOldGenExpand_lock      = nullptr;
 61 #endif
 62 Mutex*   AdapterHandlerLibrary_lock   = nullptr;
 63 Mutex*   SignatureHandlerLibrary_lock = nullptr;
 64 Mutex*   VtableStubs_lock             = nullptr;
 65 Mutex*   SymbolArena_lock             = nullptr;
 66 Monitor* StringDedup_lock             = nullptr;
 67 Mutex*   StringDedupIntern_lock       = nullptr;
 68 Monitor* CodeCache_lock               = nullptr;
 69 Mutex*   TouchedMethodLog_lock        = nullptr;
 70 Mutex*   RetData_lock                 = nullptr;
 71 Monitor* VMOperation_lock             = nullptr;
 72 Monitor* Threads_lock                 = nullptr;
 73 Mutex*   NonJavaThreadsList_lock      = nullptr;
 74 Mutex*   NonJavaThreadsListSync_lock  = nullptr;
 75 Monitor* CGC_lock                     = nullptr;
 76 Monitor* STS_lock                     = nullptr;
 77 Monitor* G1OldGCCount_lock            = nullptr;
 78 Mutex*   G1RareEvent_lock             = nullptr;
 79 Mutex*   G1DetachedRefinementStats_lock = nullptr;
 80 Mutex*   MarkStackFreeList_lock       = nullptr;
 81 Mutex*   MarkStackChunkList_lock      = nullptr;
 82 Mutex*   MonitoringSupport_lock       = nullptr;
 83 Monitor* ConcurrentGCBreakpoints_lock = nullptr;
 84 Mutex*   Compile_lock                 = nullptr;
 85 Monitor* MethodCompileQueue_lock      = nullptr;
 86 Monitor* MethodCompileQueueC1_lock    = nullptr;
 87 Monitor* MethodCompileQueueC2_lock    = nullptr;
 88 Monitor* MethodCompileQueueC3_lock    = nullptr;
 89 Monitor* MethodCompileQueueSC1_lock   = nullptr;
 90 Monitor* MethodCompileQueueSC2_lock   = nullptr;
 91 Monitor* CompileThread_lock           = nullptr;
 92 Monitor* Compilation_lock             = nullptr;
 93 Mutex*   CompileTaskAlloc_lock        = nullptr;
 94 Mutex*   CompileStatistics_lock       = nullptr;
 95 Mutex*   DirectivesStack_lock         = nullptr;
 96 Monitor* Terminator_lock              = nullptr;
 97 Monitor* InitCompleted_lock           = nullptr;
 98 Monitor* BeforeExit_lock              = nullptr;
 99 Monitor* Notify_lock                  = nullptr;
100 Mutex*   ExceptionCache_lock          = nullptr;
101 Mutex*   TrainingData_lock            = nullptr;
102 Monitor* TrainingReplayQueue_lock     = nullptr;
103 #ifndef PRODUCT
104 Mutex*   FullGCALot_lock              = nullptr;
105 #endif
106 
107 Mutex*   tty_lock                     = nullptr;
108 
109 Mutex*   RawMonitor_lock              = nullptr;
110 Mutex*   PerfDataMemAlloc_lock        = nullptr;
111 Mutex*   PerfDataManager_lock         = nullptr;
112 
113 Mutex*   FreeList_lock                = nullptr;
114 Mutex*   OldSets_lock                 = nullptr;
115 Mutex*   Uncommit_lock                = nullptr;
116 Monitor* RootRegionScan_lock          = nullptr;
117 
118 Mutex*   Management_lock              = nullptr;
119 Monitor* MonitorDeflation_lock        = nullptr;
120 Monitor* Service_lock                 = nullptr;
121 Monitor* Notification_lock            = nullptr;
122 Monitor* PeriodicTask_lock            = nullptr;
123 Monitor* RedefineClasses_lock         = nullptr;
124 Mutex*   Verify_lock                  = nullptr;
125 
126 #if INCLUDE_JFR
127 Mutex*   JfrStacktrace_lock           = nullptr;
128 Monitor* JfrMsg_lock                  = nullptr;
129 Mutex*   JfrBuffer_lock               = nullptr;
130 Monitor* JfrThreadSampler_lock        = nullptr;
131 #endif
132 
133 Mutex*   CodeHeapStateAnalytics_lock  = nullptr;
134 
135 Mutex*   ExternalsRecorder_lock       = nullptr;
136 
137 Monitor* ContinuationRelativize_lock  = nullptr;
138 
139 Mutex*   Metaspace_lock               = nullptr;
140 Monitor* MetaspaceCritical_lock       = nullptr;
141 Mutex*   ClassLoaderDataGraph_lock    = nullptr;
142 Monitor* ThreadsSMRDelete_lock        = nullptr;
143 Mutex*   ThreadIdTableCreate_lock     = nullptr;
144 Mutex*   SharedDecoder_lock           = nullptr;
145 Mutex*   DCmdFactory_lock             = nullptr;
146 Mutex*   NMTQuery_lock                = nullptr;
147 Mutex*   NMTCompilationCostHistory_lock = nullptr;
148 
149 #if INCLUDE_CDS
150 #if INCLUDE_JVMTI
151 Mutex*   CDSClassFileStream_lock      = nullptr;
152 #endif
153 Mutex*   DumpTimeTable_lock           = nullptr;
154 Mutex*   CDSLambda_lock               = nullptr;
155 Mutex*   DumpRegion_lock              = nullptr;
156 Mutex*   ClassListFile_lock           = nullptr;
157 Mutex*   UnregisteredClassesTable_lock= nullptr;
158 Mutex*   LambdaFormInvokers_lock      = nullptr;
159 Mutex*   ScratchObjects_lock          = nullptr;
160 Mutex*   ArchivedObjectTables_lock    = nullptr;
161 #endif // INCLUDE_CDS
162 Mutex*   Bootclasspath_lock           = nullptr;
163 
164 #if INCLUDE_JVMCI
165 Monitor* JVMCI_lock                   = nullptr;
166 Monitor* JVMCIRuntime_lock            = nullptr;
167 #endif
168 
169 // Only one RecursiveMutex
170 RecursiveMutex* MultiArray_lock       = nullptr;
171 
172 #define MAX_NUM_MUTEX 128
173 static Mutex* _mutex_array[MAX_NUM_MUTEX];
174 static int _num_mutex;
175 
176 #ifdef ASSERT
177 void assert_locked_or_safepoint(const Mutex* lock) {
178   if (DebuggingContext::is_enabled() || VMError::is_error_reported()) return;
179   // check if this thread owns the lock (common case)
180   assert(lock != nullptr, "Need non-null lock");
181   if (lock->owned_by_self()) return;
182   if (SafepointSynchronize::is_at_safepoint()) return;
183   if (!Universe::is_fully_initialized()) return;
184   fatal("must own lock %s", lock->name());
185 }
186 
187 // a stronger assertion than the above
188 void assert_lock_strong(const Mutex* lock) {
189   if (DebuggingContext::is_enabled() || VMError::is_error_reported()) return;
190   assert(lock != nullptr, "Need non-null lock");
191   if (lock->owned_by_self()) return;
192   fatal("must own lock %s", lock->name());
193 }
194 #endif
195 
196 static void add_mutex(Mutex* var) {
197   assert(_num_mutex < MAX_NUM_MUTEX, "increase MAX_NUM_MUTEX");
198   int id = _num_mutex++;
199   _mutex_array[id] = var;
200 //  var->set_id(id);
201 }
202 
203 #define MUTEX_STORAGE_NAME(name) name##_storage
204 #define MUTEX_STORAGE(name, type) alignas(type) static uint8_t MUTEX_STORAGE_NAME(name)[sizeof(type)]
205 #define MUTEX_DEF(name, type, pri, ...) {                                                       \
206   assert(name == nullptr, "Mutex/Monitor initialized twice");                                   \
207   MUTEX_STORAGE(name, type);                                                                    \
208   name = ::new(static_cast<void*>(MUTEX_STORAGE_NAME(name))) type((pri), #name, ##__VA_ARGS__); \
209   add_mutex(name);                                                                              \
210 }
211 #define MUTEX_DEFN(name, type, pri, ...) MUTEX_DEF(name, type, Mutex::pri, ##__VA_ARGS__)
212 
213 // Specify relative ranked lock
214 #ifdef ASSERT
215 #define MUTEX_DEFL(name, type, held_lock, ...) MUTEX_DEF(name, type, (held_lock)->rank() - 1, ##__VA_ARGS__)
216 #else
217 #define MUTEX_DEFL(name, type, held_lock, ...) MUTEX_DEFN(name, type, safepoint, ##__VA_ARGS__)
218 #endif
219 
220 // Using Padded subclasses to prevent false sharing of these global monitors and mutexes.
221 void mutex_init() {
222   MUTEX_DEFN(tty_lock                        , PaddedMutex  , tty);      // allow to lock in VM
223 
224   MUTEX_DEFN(STS_lock                        , PaddedMonitor, nosafepoint);
225 
226   if (UseG1GC) {
227     MUTEX_DEFN(CGC_lock                      , PaddedMonitor, nosafepoint);
228 
229     MUTEX_DEFN(G1DetachedRefinementStats_lock, PaddedMutex  , nosafepoint-2);
230 
231     MUTEX_DEFN(FreeList_lock                 , PaddedMutex  , service-1);
232     MUTEX_DEFN(OldSets_lock                  , PaddedMutex  , nosafepoint);
233     MUTEX_DEFN(Uncommit_lock                 , PaddedMutex  , service-2);
234     MUTEX_DEFN(RootRegionScan_lock           , PaddedMonitor, nosafepoint-1);
235 
236     MUTEX_DEFN(MarkStackFreeList_lock        , PaddedMutex  , nosafepoint);
237     MUTEX_DEFN(MarkStackChunkList_lock       , PaddedMutex  , nosafepoint);
238   }
239   MUTEX_DEFN(MonitoringSupport_lock          , PaddedMutex  , service-1);        // used for serviceability monitoring support
240 
241   MUTEX_DEFN(StringDedup_lock                , PaddedMonitor, nosafepoint);
242   MUTEX_DEFN(StringDedupIntern_lock          , PaddedMutex  , nosafepoint);
243   MUTEX_DEFN(RawMonitor_lock                 , PaddedMutex  , nosafepoint-1);
244 
245   MUTEX_DEFN(Metaspace_lock                  , PaddedMutex  , nosafepoint-3);
246   MUTEX_DEFN(MetaspaceCritical_lock          , PaddedMonitor, nosafepoint-1);
247 
248   MUTEX_DEFN(Patching_lock                   , PaddedMutex  , nosafepoint);      // used for safepointing and code patching.
249   MUTEX_DEFN(MonitorDeflation_lock           , PaddedMonitor, nosafepoint);      // used for monitor deflation thread operations
250   MUTEX_DEFN(Service_lock                    , PaddedMonitor, service);          // used for service thread operations
251   MUTEX_DEFN(Notification_lock               , PaddedMonitor, service);          // used for notification thread operations
252 
253   MUTEX_DEFN(JmethodIdCreation_lock          , PaddedMutex  , nosafepoint-2); // used for creating jmethodIDs.
254   MUTEX_DEFN(InvokeMethodTypeTable_lock      , PaddedMutex  , safepoint);
255   MUTEX_DEFN(InvokeMethodIntrinsicTable_lock , PaddedMonitor, safepoint);
256   MUTEX_DEFN(AdapterHandlerLibrary_lock      , PaddedMutex  , safepoint);
257   MUTEX_DEFN(SharedDictionary_lock           , PaddedMutex  , safepoint);
258   MUTEX_DEFN(VMStatistic_lock                , PaddedMutex  , safepoint);
259   MUTEX_DEFN(SignatureHandlerLibrary_lock    , PaddedMutex  , safepoint);
260   MUTEX_DEFN(SymbolArena_lock                , PaddedMutex  , nosafepoint);
261   MUTEX_DEFN(ExceptionCache_lock             , PaddedMutex  , safepoint);
262 #ifndef PRODUCT
263   MUTEX_DEFN(FullGCALot_lock                 , PaddedMutex  , safepoint); // a lock to make FullGCALot MT safe
264 #endif
265   MUTEX_DEFN(BeforeExit_lock                 , PaddedMonitor, safepoint);
266 
267   MUTEX_DEFN(NonJavaThreadsList_lock         , PaddedMutex  , nosafepoint-1);
268   MUTEX_DEFN(NonJavaThreadsListSync_lock     , PaddedMutex  , nosafepoint);
269 
270   MUTEX_DEFN(RetData_lock                    , PaddedMutex  , safepoint);
271   MUTEX_DEFN(Terminator_lock                 , PaddedMonitor, safepoint, true);
272   MUTEX_DEFN(InitCompleted_lock              , PaddedMonitor, nosafepoint);
273   MUTEX_DEFN(Notify_lock                     , PaddedMonitor, safepoint, true);
274 
275   MUTEX_DEFN(JfieldIdCreation_lock           , PaddedMutex  , safepoint);
276 
277   MUTEX_DEFN(CompiledIC_lock                 , PaddedMutex  , nosafepoint);  // locks VtableStubs_lock
278   MUTEX_DEFN(MethodCompileQueue_lock         , PaddedMonitor, safepoint);
279   if (UseGlobalCompileQueueLock) {
280     MethodCompileQueueC1_lock  = MethodCompileQueue_lock;
281     MethodCompileQueueC2_lock  = MethodCompileQueue_lock;
282     MethodCompileQueueC3_lock  = MethodCompileQueue_lock;
283     MethodCompileQueueSC1_lock = MethodCompileQueue_lock;
284     MethodCompileQueueSC2_lock = MethodCompileQueue_lock;
285   } else {
286     MUTEX_DEFN(MethodCompileQueueC1_lock     , PaddedMonitor, safepoint);
287     MUTEX_DEFN(MethodCompileQueueC2_lock     , PaddedMonitor, safepoint);
288     MUTEX_DEFN(MethodCompileQueueC3_lock     , PaddedMonitor, safepoint);
289     MUTEX_DEFN(MethodCompileQueueSC1_lock    , PaddedMonitor, safepoint);
290     MUTEX_DEFN(MethodCompileQueueSC2_lock    , PaddedMonitor, safepoint);
291   }
292   MUTEX_DEFL(TrainingData_lock               , PaddedMutex  , MethodCompileQueue_lock);
293   MUTEX_DEFN(TrainingReplayQueue_lock        , PaddedMonitor, safepoint);
294   MUTEX_DEFN(CompileStatistics_lock          , PaddedMutex  , safepoint);
295   MUTEX_DEFN(DirectivesStack_lock            , PaddedMutex  , nosafepoint);
296 
297   MUTEX_DEFN(JvmtiVTMSTransition_lock        , PaddedMonitor, safepoint);   // used for Virtual Thread Mount State transition management
298   MUTEX_DEFN(EscapeBarrier_lock              , PaddedMonitor, nosafepoint); // Used to synchronize object reallocation/relocking triggered by JVMTI
299   MUTEX_DEFN(Management_lock                 , PaddedMutex  , safepoint);   // used for JVM management
300 
301   MUTEX_DEFN(ConcurrentGCBreakpoints_lock    , PaddedMonitor, safepoint, true);
302   MUTEX_DEFN(TouchedMethodLog_lock           , PaddedMutex  , safepoint);
303 
304   MUTEX_DEFN(CompileThread_lock              , PaddedMonitor, safepoint);
305   MUTEX_DEFN(PeriodicTask_lock               , PaddedMonitor, safepoint, true);
306   MUTEX_DEFN(RedefineClasses_lock            , PaddedMonitor, safepoint);
307   MUTEX_DEFN(Verify_lock                     , PaddedMutex  , safepoint);
308   MUTEX_DEFN(ClassLoaderDataGraph_lock       , PaddedMutex  , safepoint);
309 
310   MUTEX_DEFN(Compilation_lock                , PaddedMonitor, nosafepoint);
311 
312 #if INCLUDE_JFR
313   MUTEX_DEFN(JfrBuffer_lock                  , PaddedMutex  , event);
314   MUTEX_DEFN(JfrMsg_lock                     , PaddedMonitor, event);
315   MUTEX_DEFN(JfrStacktrace_lock              , PaddedMutex  , event);
316   MUTEX_DEFN(JfrThreadSampler_lock           , PaddedMonitor, nosafepoint);
317 #endif
318 
319   MUTEX_DEFN(ContinuationRelativize_lock     , PaddedMonitor, nosafepoint-3);
320   MUTEX_DEFN(CodeHeapStateAnalytics_lock     , PaddedMutex  , safepoint);
321   MUTEX_DEFN(ThreadsSMRDelete_lock           , PaddedMonitor, service-2); // Holds ConcurrentHashTableResize_lock
322   MUTEX_DEFN(ThreadIdTableCreate_lock        , PaddedMutex  , safepoint);
323   MUTEX_DEFN(SharedDecoder_lock              , PaddedMutex  , tty-1);
324   MUTEX_DEFN(DCmdFactory_lock                , PaddedMutex  , nosafepoint);
325   MUTEX_DEFN(NMTQuery_lock                   , PaddedMutex  , safepoint);
326   MUTEX_DEFN(NMTCompilationCostHistory_lock  , PaddedMutex  , nosafepoint);
327 #if INCLUDE_CDS
328 #if INCLUDE_JVMTI
329   MUTEX_DEFN(CDSClassFileStream_lock         , PaddedMutex  , safepoint);
330 #endif
331   MUTEX_DEFN(DumpTimeTable_lock              , PaddedMutex  , nosafepoint);
332   MUTEX_DEFN(CDSLambda_lock                  , PaddedMutex  , nosafepoint);
333   MUTEX_DEFN(DumpRegion_lock                 , PaddedMutex  , nosafepoint);
334   MUTEX_DEFN(ClassListFile_lock              , PaddedMutex  , nosafepoint);
335   MUTEX_DEFN(UnregisteredClassesTable_lock   , PaddedMutex  , nosafepoint-1);
336   MUTEX_DEFN(LambdaFormInvokers_lock         , PaddedMutex  , safepoint);
337   MUTEX_DEFN(ScratchObjects_lock             , PaddedMutex  , nosafepoint-1); // Holds DumpTimeTable_lock
338   MUTEX_DEFN(ArchivedObjectTables_lock       , PaddedMutex  , nosafepoint);
339 #endif // INCLUDE_CDS
340   MUTEX_DEFN(Bootclasspath_lock              , PaddedMutex  , nosafepoint);
341 
342 #if INCLUDE_JVMCI
343   // JVMCIRuntime::_lock must be acquired before JVMCI_lock to avoid deadlock
344   MUTEX_DEFN(JVMCIRuntime_lock               , PaddedMonitor, safepoint, true);
345 #endif
346 
347   // These locks have relative rankings, and inherit safepoint checking attributes from that rank.
348   MUTEX_DEFL(VtableStubs_lock               , PaddedMutex  , CompiledIC_lock);  // Also holds DumpTimeTable_lock
349   MUTEX_DEFL(CodeCache_lock                 , PaddedMonitor, VtableStubs_lock);
350   MUTEX_DEFL(NMethodState_lock              , PaddedMutex  , CodeCache_lock);
351 
352   // tty_lock is held when printing nmethod and its relocations which use this lock.
353   MUTEX_DEFL(ExternalsRecorder_lock         , PaddedMutex  , tty_lock);
354 
355   MUTEX_DEFL(Threads_lock                   , PaddedMonitor, CompileThread_lock, true);
356   MUTEX_DEFL(Compile_lock                   , PaddedMutex  , MethodCompileQueue_lock);
357   MUTEX_DEFL(Heap_lock                      , PaddedMonitor, TrainingData_lock  /*AdapterHandlerLibrary_lock*/);
358 
359   MUTEX_DEFL(PerfDataMemAlloc_lock          , PaddedMutex  , Heap_lock);
360   MUTEX_DEFL(PerfDataManager_lock           , PaddedMutex  , Heap_lock);
361   MUTEX_DEFL(VMOperation_lock               , PaddedMonitor, Heap_lock, true);
362   MUTEX_DEFL(ClassInitError_lock            , PaddedMonitor, Threads_lock);
363 
364   if (UseG1GC) {
365     MUTEX_DEFL(G1OldGCCount_lock            , PaddedMonitor, Threads_lock, true);
366     MUTEX_DEFL(G1RareEvent_lock             , PaddedMutex  , Threads_lock, true);
367   }
368 
369   MUTEX_DEFL(CompileTaskAlloc_lock          , PaddedMutex  ,  MethodCompileQueue_lock);
370 #ifdef INCLUDE_PARALLELGC
371   if (UseParallelGC) {
372     MUTEX_DEFL(PSOldGenExpand_lock          , PaddedMutex  , Heap_lock, true);
373   }
374 #endif
375   MUTEX_DEFL(Module_lock                    , PaddedMutex  ,  ClassLoaderDataGraph_lock);
376   MUTEX_DEFL(SystemDictionary_lock          , PaddedMonitor, Module_lock);
377   MUTEX_DEFL(JNICritical_lock               , PaddedMonitor, AdapterHandlerLibrary_lock); // used for JNI critical regions
378 #if INCLUDE_JVMCI
379   // JVMCIRuntime_lock must be acquired before JVMCI_lock to avoid deadlock
380   MUTEX_DEFL(JVMCI_lock                     , PaddedMonitor, JVMCIRuntime_lock);
381 #endif
382   MUTEX_DEFL(JvmtiThreadState_lock          , PaddedMutex  , JvmtiVTMSTransition_lock);   // Used by JvmtiThreadState/JvmtiEventController
383 
384   // Allocate RecursiveMutex
385   MultiArray_lock = new RecursiveMutex();
386 }
387 
388 #undef MUTEX_DEFL
389 #undef MUTEX_DEFN
390 #undef MUTEX_DEF
391 #undef MUTEX_STORAGE
392 #undef MUTEX_STORAGE_NAME
393 
394 static const int MAX_NAMES = 200;
395 static const char* _names[MAX_NAMES] = { nullptr };
396 static bool _is_unique[MAX_NAMES] = { false };
397 static int _num_names = 0;
398 
399 PerfCounter** MutexLockerImpl::_perf_lock_count     = nullptr;
400 PerfCounter** MutexLockerImpl::_perf_lock_wait_time = nullptr;
401 PerfCounter** MutexLockerImpl::_perf_lock_hold_time = nullptr;
402 
403 void MutexLockerImpl::init_counters() {
404   if (ProfileVMLocks && UsePerfData) {
405     ResourceMark rm;
406     EXCEPTION_MARK;
407     _perf_lock_count     = NEW_C_HEAP_ARRAY(PerfCounter*, MAX_NAMES + 1, mtInternal);
408     _perf_lock_wait_time = NEW_C_HEAP_ARRAY(PerfCounter*, MAX_NAMES + 1, mtInternal);
409     _perf_lock_hold_time = NEW_C_HEAP_ARRAY(PerfCounter*, MAX_NAMES + 1, mtInternal);
410 
411     NEWPERFEVENTCOUNTER(_perf_lock_count[0],     SUN_RT, PerfDataManager::counter_name("Other", "Count"));
412     NEWPERFEVENTCOUNTER(_perf_lock_wait_time[0], SUN_RT, PerfDataManager::counter_name("Other", "BeforeTime"));
413     NEWPERFEVENTCOUNTER(_perf_lock_hold_time[0], SUN_RT, PerfDataManager::counter_name("Other", "AfterTime"));
414     for (int i = 0; i < MAX_NAMES; i++) {
415       ResourceMark rm;
416       const char* counter_name = _names[i];
417       if (counter_name == nullptr) {
418         stringStream ss;
419         ss.print("UnnamedMutex#%d", i);
420         counter_name = ss.as_string();
421       }
422       NEWPERFEVENTCOUNTER(_perf_lock_count[i + 1],     SUN_RT, PerfDataManager::counter_name(counter_name, "Count"));
423       NEWPERFEVENTCOUNTER(_perf_lock_wait_time[i + 1], SUN_RT, PerfDataManager::counter_name(counter_name, "BeforeTime"));
424       NEWPERFEVENTCOUNTER(_perf_lock_hold_time[i + 1], SUN_RT, PerfDataManager::counter_name(counter_name, "AfterTime"));
425     }
426     if (HAS_PENDING_EXCEPTION) {
427       vm_exit_during_initialization("MutexLockerImpl::init_counters() failed unexpectedly");
428     }
429   }
430 }
431 
432 int MutexLockerImpl::name2id(const char* name) {
433   if (ProfileVMLocks && UsePerfData) {
434     for (int i = 0; i < _num_names; i++) {
435       if (strcmp(_names[i], name) == 0) {
436         _is_unique[i] = false;
437         return i;
438       }
439     }
440     if (_num_names < MAX_NAMES) {
441       int new_id = _num_names++;
442       _names[new_id] = os::strdup(name, mtInternal);
443       _is_unique[new_id] = true;
444       return new_id;
445     }
446     log_debug(init)("Unnamed: %s", name); // no slots left
447   }
448   return -1;
449 }
450 
451 void MutexLockerImpl::print_counter_on(outputStream* st, const char* name, bool is_unique, int idx) {
452   jlong count = _perf_lock_count[idx]->get_value();
453   if (count > 0) {
454     st->print_cr("  %3d: %s%40s = " JLONG_FORMAT_W(5) "us (" JLONG_FORMAT_W(5) "us) / " JLONG_FORMAT_W(9) " events",
455                  idx, (is_unique ? " " : "M"), name,
456                  Management::ticks_to_us(_perf_lock_hold_time[idx]->get_value()),
457                  Management::ticks_to_us(_perf_lock_wait_time[idx]->get_value()),
458                  count);
459   }
460 }
461 
462 static jlong accumulate_lock_counters(PerfCounter** lock_counters) {
463   jlong acc = 0;
464   for (int i = 0; i < _num_names + 1; i++) { // 0 slot is reserved for unnamed locks
465     if (lock_counters[i] == nullptr) {
466       break;
467     }
468     acc += lock_counters[i]->get_value();
469   }
470   return acc;
471 }
472 
473 void MutexLockerImpl::print_counters_on(outputStream* st) {
474   if (ProfileVMLocks && UsePerfData) {
475     jlong total_count     = accumulate_lock_counters(_perf_lock_count);
476     jlong total_wait_time = accumulate_lock_counters(_perf_lock_wait_time);
477     jlong total_hold_time = accumulate_lock_counters(_perf_lock_hold_time);
478 
479     st->print_cr("MutexLocker: Total: %d named locks (%d unique names); hold = " JLONG_FORMAT "us (wait = " JLONG_FORMAT "us) / " JLONG_FORMAT " events for thread \"main\"",
480                  _num_mutex, _num_names,
481                  Management::ticks_to_us(total_hold_time),
482                  Management::ticks_to_us(total_wait_time),
483                  total_count);
484     for (int i = 0; i < _num_names; i++) {
485       print_counter_on(st, _names[i], _is_unique[i], i+1);
486     }
487     print_counter_on(st, "Unnamed / Other", false /*is_unique*/, 0);
488   } else {
489     st->print_cr("MutexLocker: no info (%s is disabled)", (UsePerfData ? "ProfileVMLocks" : "UsePerfData"));
490   }
491 }
492 
493 void MutexLockerImpl::post_initialize() {
494   // Print mutex ranks if requested.
495   LogTarget(Info, vmmutex) lt;
496   if (lt.is_enabled()) {
497     ResourceMark rm;
498     LogStream ls(lt);
499     print_lock_ranks(&ls);
500   }
501 }
502 
503 GCMutexLocker::GCMutexLocker(Mutex* mutex) {
504   if (SafepointSynchronize::is_at_safepoint()) {
505     _locked = false;
506   } else {
507     _mutex = mutex;
508     _locked = true;
509     _mutex->lock();
510   }
511 }
512 
513 // Print all mutexes/monitors that are currently owned by a thread; called
514 // by fatal error handler.
515 void print_owned_locks_on_error(outputStream* st) {
516   st->print("VM Mutex/Monitor currently owned by a thread: ");
517   bool none = true;
518   for (int i = 0; i < _num_mutex; i++) {
519      // see if it has an owner
520      if (_mutex_array[i]->owner() != nullptr) {
521        if (none) {
522           // print format used by Mutex::print_on_error()
523           st->print_cr(" ([mutex/lock_event])");
524           none = false;
525        }
526        _mutex_array[i]->print_on_error(st);
527        st->cr();
528      }
529   }
530   if (none) st->print_cr("None");
531 }
532 
533 void print_lock_ranks(outputStream* st) {
534   st->print_cr("VM Mutex/Monitor ranks: ");
535 
536 #ifdef ASSERT
537   // Be extra defensive and figure out the bounds on
538   // ranks right here. This also saves a bit of time
539   // in the #ranks*#mutexes loop below.
540   int min_rank = INT_MAX;
541   int max_rank = INT_MIN;
542   for (int i = 0; i < _num_mutex; i++) {
543     Mutex* m = _mutex_array[i];
544     int r = (int) m->rank();
545     if (min_rank > r) min_rank = r;
546     if (max_rank < r) max_rank = r;
547   }
548 
549   // Print the listings rank by rank
550   for (int r = min_rank; r <= max_rank; r++) {
551     bool first = true;
552     for (int i = 0; i < _num_mutex; i++) {
553       Mutex* m = _mutex_array[i];
554       if (r != (int) m->rank()) continue;
555 
556       if (first) {
557         st->cr();
558         st->print_cr("Rank \"%s\":", m->rank_name());
559         first = false;
560       }
561       st->print_cr("  %s", m->name());
562     }
563   }
564 #else
565   st->print_cr("  Only known in debug builds.");
566 #endif // ASSERT
567 }