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*   NMethodState_lock            = nullptr;
 43 Monitor* SystemDictionary_lock        = nullptr;
 44 Mutex*   InvokeMethodTypeTable_lock   = nullptr;
 45 Monitor* InvokeMethodIntrinsicTable_lock = nullptr;
 46 Mutex*   SharedDictionary_lock        = nullptr;
 47 Monitor* ClassInitError_lock          = nullptr;
 48 Mutex*   Module_lock                  = nullptr;
 49 Mutex*   CompiledIC_lock              = nullptr;
 50 Mutex*   VMStatistic_lock             = nullptr;
 51 Mutex*   JmethodIdCreation_lock       = nullptr;
 52 Mutex*   JfieldIdCreation_lock        = nullptr;
 53 Monitor* JNICritical_lock             = nullptr;
 54 Mutex*   JvmtiThreadState_lock        = nullptr;
 55 Monitor* EscapeBarrier_lock           = nullptr;
 56 Monitor* JvmtiVTMSTransition_lock     = nullptr;
 57 Monitor* Heap_lock                    = nullptr;
 58 #ifdef INCLUDE_PARALLELGC
 59 Mutex*   PSOldGenExpand_lock      = nullptr;
 60 #endif
 61 Mutex*   AdapterHandlerLibrary_lock   = nullptr;
 62 Mutex*   SignatureHandlerLibrary_lock = nullptr;
 63 Mutex*   VtableStubs_lock             = nullptr;
 64 Mutex*   SymbolArena_lock             = nullptr;
 65 Monitor* StringDedup_lock             = nullptr;
 66 Mutex*   StringDedupIntern_lock       = nullptr;
 67 Monitor* CodeCache_lock               = nullptr;
 68 Mutex*   TouchedMethodLog_lock        = nullptr;
 69 Mutex*   RetData_lock                 = nullptr;
 70 Monitor* VMOperation_lock             = nullptr;
 71 Monitor* ThreadsLockThrottle_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 #ifdef ASSERT
173 void assert_locked_or_safepoint(const Mutex* lock) {
174   if (DebuggingContext::is_enabled() || VMError::is_error_reported()) return;
175   // check if this thread owns the lock (common case)
176   assert(lock != nullptr, "Need non-null lock");
177   if (lock->owned_by_self()) 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 (DebuggingContext::is_enabled() || VMError::is_error_reported()) return;
186   assert(lock != nullptr, "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 MUTEX_STORAGE_NAME(name) name##_storage
193 #define MUTEX_STORAGE(name, type) alignas(type) static uint8_t MUTEX_STORAGE_NAME(name)[sizeof(type)]
194 #define MUTEX_DEF(name, type, pri, ...) {                                                       \
195   assert(name == nullptr, "Mutex/Monitor initialized twice");                                   \
196   MUTEX_STORAGE(name, type);                                                                    \
197   name = ::new(static_cast<void*>(MUTEX_STORAGE_NAME(name))) type((pri), #name, ##__VA_ARGS__); \
198   Mutex::add_mutex(name);                                                                       \
199 }
200 #define MUTEX_DEFN(name, type, pri, ...) MUTEX_DEF(name, type, Mutex::pri, ##__VA_ARGS__)
201 
202 // Specify relative ranked lock
203 #ifdef ASSERT
204 #define MUTEX_DEFL(name, type, held_lock, ...) MUTEX_DEF(name, type, (held_lock)->rank() - 1, ##__VA_ARGS__)
205 #else
206 #define MUTEX_DEFL(name, type, held_lock, ...) MUTEX_DEFN(name, type, safepoint, ##__VA_ARGS__)
207 #endif
208 
209 // Using Padded subclasses to prevent false sharing of these global monitors and mutexes.
210 void mutex_init() {
211   MUTEX_DEFN(tty_lock                        , PaddedMutex  , tty);      // allow to lock in VM
212 
213   MUTEX_DEFN(STS_lock                        , PaddedMonitor, nosafepoint);
214 
215   if (UseG1GC) {
216     MUTEX_DEFN(CGC_lock                      , PaddedMonitor, nosafepoint);
217 
218     MUTEX_DEFN(G1DetachedRefinementStats_lock, PaddedMutex  , nosafepoint-2);
219 
220     MUTEX_DEFN(FreeList_lock                 , PaddedMutex  , service-1);
221     MUTEX_DEFN(OldSets_lock                  , PaddedMutex  , nosafepoint);
222     MUTEX_DEFN(Uncommit_lock                 , PaddedMutex  , service-2);
223     MUTEX_DEFN(RootRegionScan_lock           , PaddedMonitor, nosafepoint-1);
224 
225     MUTEX_DEFN(MarkStackFreeList_lock        , PaddedMutex  , nosafepoint);
226     MUTEX_DEFN(MarkStackChunkList_lock       , PaddedMutex  , nosafepoint);
227   }
228   MUTEX_DEFN(MonitoringSupport_lock          , PaddedMutex  , service-1);        // used for serviceability monitoring support
229 
230   MUTEX_DEFN(StringDedup_lock                , PaddedMonitor, nosafepoint);
231   MUTEX_DEFN(StringDedupIntern_lock          , PaddedMutex  , nosafepoint);
232   MUTEX_DEFN(RawMonitor_lock                 , PaddedMutex  , nosafepoint-1);
233 
234   MUTEX_DEFN(Metaspace_lock                  , PaddedMutex  , nosafepoint-3);
235   MUTEX_DEFN(MetaspaceCritical_lock          , PaddedMonitor, nosafepoint-1);
236 
237   MUTEX_DEFN(MonitorDeflation_lock           , PaddedMonitor, nosafepoint);      // used for monitor deflation thread operations
238   MUTEX_DEFN(Service_lock                    , PaddedMonitor, service);          // used for service thread operations
239   MUTEX_DEFN(Notification_lock               , PaddedMonitor, service);          // used for notification thread operations
240 
241   MUTEX_DEFN(JmethodIdCreation_lock          , PaddedMutex  , nosafepoint-2); // used for creating jmethodIDs.
242   MUTEX_DEFN(InvokeMethodTypeTable_lock      , PaddedMutex  , safepoint);
243   MUTEX_DEFN(InvokeMethodIntrinsicTable_lock , PaddedMonitor, safepoint);
244   MUTEX_DEFN(AdapterHandlerLibrary_lock      , PaddedMutex  , safepoint);
245   MUTEX_DEFN(SharedDictionary_lock           , PaddedMutex  , safepoint);
246   MUTEX_DEFN(VMStatistic_lock                , PaddedMutex  , safepoint);
247   MUTEX_DEFN(SignatureHandlerLibrary_lock    , PaddedMutex  , safepoint);
248   MUTEX_DEFN(SymbolArena_lock                , PaddedMutex  , nosafepoint);
249   MUTEX_DEFN(ExceptionCache_lock             , PaddedMutex  , safepoint);
250 #ifndef PRODUCT
251   MUTEX_DEFN(FullGCALot_lock                 , PaddedMutex  , safepoint); // a lock to make FullGCALot MT safe
252 #endif
253   MUTEX_DEFN(BeforeExit_lock                 , PaddedMonitor, safepoint);
254 
255   MUTEX_DEFN(NonJavaThreadsList_lock         , PaddedMutex  , nosafepoint-1);
256   MUTEX_DEFN(NonJavaThreadsListSync_lock     , PaddedMutex  , nosafepoint);
257 
258   MUTEX_DEFN(RetData_lock                    , PaddedMutex  , safepoint);
259   MUTEX_DEFN(Terminator_lock                 , PaddedMonitor, safepoint, true);
260   MUTEX_DEFN(InitCompleted_lock              , PaddedMonitor, nosafepoint);
261   MUTEX_DEFN(Notify_lock                     , PaddedMonitor, safepoint, true);
262 
263   MUTEX_DEFN(JfieldIdCreation_lock           , PaddedMutex  , safepoint);
264 
265   MUTEX_DEFN(CompiledIC_lock                 , PaddedMutex  , nosafepoint);  // locks VtableStubs_lock
266   MUTEX_DEFN(MethodCompileQueue_lock         , PaddedMonitor, safepoint);
267   if (UseGlobalCompileQueueLock) {
268     MethodCompileQueueC1_lock  = MethodCompileQueue_lock;
269     MethodCompileQueueC2_lock  = MethodCompileQueue_lock;
270     MethodCompileQueueC3_lock  = MethodCompileQueue_lock;
271     MethodCompileQueueSC1_lock = MethodCompileQueue_lock;
272     MethodCompileQueueSC2_lock = MethodCompileQueue_lock;
273   } else {
274     MUTEX_DEFN(MethodCompileQueueC1_lock     , PaddedMonitor, safepoint);
275     MUTEX_DEFN(MethodCompileQueueC2_lock     , PaddedMonitor, safepoint);
276     MUTEX_DEFN(MethodCompileQueueC3_lock     , PaddedMonitor, safepoint);
277     MUTEX_DEFN(MethodCompileQueueSC1_lock    , PaddedMonitor, safepoint);
278     MUTEX_DEFN(MethodCompileQueueSC2_lock    , PaddedMonitor, safepoint);
279   }
280   MUTEX_DEFL(TrainingData_lock               , PaddedMutex  , MethodCompileQueue_lock);
281   MUTEX_DEFN(TrainingReplayQueue_lock        , PaddedMonitor, safepoint);
282   MUTEX_DEFN(CompileStatistics_lock          , PaddedMutex  , safepoint);
283   MUTEX_DEFN(DirectivesStack_lock            , PaddedMutex  , nosafepoint);
284 
285   MUTEX_DEFN(JvmtiVTMSTransition_lock        , PaddedMonitor, safepoint);   // used for Virtual Thread Mount State transition management
286   MUTEX_DEFN(EscapeBarrier_lock              , PaddedMonitor, nosafepoint); // Used to synchronize object reallocation/relocking triggered by JVMTI
287   MUTEX_DEFN(Management_lock                 , PaddedMutex  , safepoint);   // used for JVM management
288 
289   MUTEX_DEFN(ConcurrentGCBreakpoints_lock    , PaddedMonitor, safepoint, true);
290   MUTEX_DEFN(TouchedMethodLog_lock           , PaddedMutex  , safepoint);
291 
292   MUTEX_DEFN(CompileThread_lock              , PaddedMonitor, safepoint);
293   MUTEX_DEFN(PeriodicTask_lock               , PaddedMonitor, safepoint, true);
294   MUTEX_DEFN(RedefineClasses_lock            , PaddedMonitor, safepoint);
295   MUTEX_DEFN(Verify_lock                     , PaddedMutex  , safepoint);
296   MUTEX_DEFN(ClassLoaderDataGraph_lock       , PaddedMutex  , safepoint);
297 
298   MUTEX_DEFN(Compilation_lock                , PaddedMonitor, nosafepoint);
299 
300 #if INCLUDE_JFR
301   MUTEX_DEFN(JfrBuffer_lock                  , PaddedMutex  , event);
302   MUTEX_DEFN(JfrMsg_lock                     , PaddedMonitor, event);
303   MUTEX_DEFN(JfrStacktrace_lock              , PaddedMutex  , event);
304   MUTEX_DEFN(JfrThreadSampler_lock           , PaddedMonitor, nosafepoint);
305 #endif
306 
307   MUTEX_DEFN(ContinuationRelativize_lock     , PaddedMonitor, nosafepoint-3);
308   MUTEX_DEFN(CodeHeapStateAnalytics_lock     , PaddedMutex  , safepoint);
309   MUTEX_DEFN(ThreadsSMRDelete_lock           , PaddedMonitor, service-2); // Holds ConcurrentHashTableResize_lock
310   MUTEX_DEFN(ThreadIdTableCreate_lock        , PaddedMutex  , safepoint);
311   MUTEX_DEFN(SharedDecoder_lock              , PaddedMutex  , tty-1);
312   MUTEX_DEFN(DCmdFactory_lock                , PaddedMutex  , nosafepoint);
313   MUTEX_DEFN(NMTQuery_lock                   , PaddedMutex  , safepoint);
314   MUTEX_DEFN(NMTCompilationCostHistory_lock  , PaddedMutex  , nosafepoint);
315 #if INCLUDE_CDS
316 #if INCLUDE_JVMTI
317   MUTEX_DEFN(CDSClassFileStream_lock         , PaddedMutex  , safepoint);
318 #endif
319   MUTEX_DEFN(DumpTimeTable_lock              , PaddedMutex  , nosafepoint);
320   MUTEX_DEFN(CDSLambda_lock                  , PaddedMutex  , nosafepoint);
321   MUTEX_DEFN(DumpRegion_lock                 , PaddedMutex  , nosafepoint);
322   MUTEX_DEFN(ClassListFile_lock              , PaddedMutex  , nosafepoint);
323   MUTEX_DEFN(UnregisteredClassesTable_lock   , PaddedMutex  , nosafepoint-1);
324   MUTEX_DEFN(LambdaFormInvokers_lock         , PaddedMutex  , safepoint);
325   MUTEX_DEFN(ScratchObjects_lock             , PaddedMutex  , nosafepoint-1); // Holds DumpTimeTable_lock
326   MUTEX_DEFN(ArchivedObjectTables_lock       , PaddedMutex  , nosafepoint);
327 #endif // INCLUDE_CDS
328   MUTEX_DEFN(Bootclasspath_lock              , PaddedMutex  , nosafepoint);
329 
330 #if INCLUDE_JVMCI
331   // JVMCIRuntime::_lock must be acquired before JVMCI_lock to avoid deadlock
332   MUTEX_DEFN(JVMCIRuntime_lock               , PaddedMonitor, safepoint, true);
333 #endif
334 
335   MUTEX_DEFN(ThreadsLockThrottle_lock        , PaddedMonitor, safepoint);
336 
337   // These locks have relative rankings, and inherit safepoint checking attributes from that rank.
338   MUTEX_DEFL(VtableStubs_lock               , PaddedMutex  , CompiledIC_lock);  // Also holds DumpTimeTable_lock
339   MUTEX_DEFL(CodeCache_lock                 , PaddedMonitor, VtableStubs_lock);
340   MUTEX_DEFL(NMethodState_lock              , PaddedMutex  , CodeCache_lock);
341 
342   // tty_lock is held when printing nmethod and its relocations which use this lock.
343   MUTEX_DEFL(ExternalsRecorder_lock         , PaddedMutex  , tty_lock);
344 
345   MUTEX_DEFL(Threads_lock                   , PaddedMonitor, CompileThread_lock, true);
346   MUTEX_DEFL(Compile_lock                   , PaddedMutex  , MethodCompileQueue_lock);
347   MUTEX_DEFL(Heap_lock                      , PaddedMonitor, TrainingData_lock  /*AdapterHandlerLibrary_lock*/);
348 
349   MUTEX_DEFL(PerfDataMemAlloc_lock          , PaddedMutex  , Heap_lock);
350   MUTEX_DEFL(PerfDataManager_lock           , PaddedMutex  , Heap_lock);
351   MUTEX_DEFL(VMOperation_lock               , PaddedMonitor, Heap_lock, true);
352   MUTEX_DEFL(ClassInitError_lock            , PaddedMonitor, Threads_lock);
353 
354   if (UseG1GC) {
355     MUTEX_DEFL(G1OldGCCount_lock            , PaddedMonitor, Threads_lock, true);
356     MUTEX_DEFL(G1RareEvent_lock             , PaddedMutex  , Threads_lock, true);
357   }
358 
359   MUTEX_DEFL(CompileTaskAlloc_lock          , PaddedMutex  ,  MethodCompileQueue_lock);
360 #ifdef INCLUDE_PARALLELGC
361   if (UseParallelGC) {
362     MUTEX_DEFL(PSOldGenExpand_lock          , PaddedMutex  , Heap_lock, true);
363   }
364 #endif
365   MUTEX_DEFL(Module_lock                    , PaddedMutex  ,  ClassLoaderDataGraph_lock);
366   MUTEX_DEFL(SystemDictionary_lock          , PaddedMonitor, Module_lock);
367   MUTEX_DEFL(JNICritical_lock               , PaddedMonitor, AdapterHandlerLibrary_lock); // used for JNI critical regions
368 #if INCLUDE_JVMCI
369   // JVMCIRuntime_lock must be acquired before JVMCI_lock to avoid deadlock
370   MUTEX_DEFL(JVMCI_lock                     , PaddedMonitor, JVMCIRuntime_lock);
371 #endif
372   MUTEX_DEFL(JvmtiThreadState_lock          , PaddedMutex  , JvmtiVTMSTransition_lock);   // Used by JvmtiThreadState/JvmtiEventController
373 
374   // Allocate RecursiveMutex
375   MultiArray_lock = new RecursiveMutex();
376 }
377 
378 #undef MUTEX_DEFL
379 #undef MUTEX_DEFN
380 #undef MUTEX_DEF
381 #undef MUTEX_STORAGE
382 #undef MUTEX_STORAGE_NAME
383 
384 static const int MAX_NAMES = 200;
385 static const char* _names[MAX_NAMES] = { nullptr };
386 static bool _is_unique[MAX_NAMES] = { false };
387 static int _num_names = 0;
388 
389 PerfCounter** MutexLockerImpl::_perf_lock_count     = nullptr;
390 PerfCounter** MutexLockerImpl::_perf_lock_wait_time = nullptr;
391 PerfCounter** MutexLockerImpl::_perf_lock_hold_time = nullptr;
392 
393 void MutexLockerImpl::init_counters() {
394   if (ProfileVMLocks && UsePerfData) {
395     ResourceMark rm;
396     EXCEPTION_MARK;
397     _perf_lock_count     = NEW_C_HEAP_ARRAY(PerfCounter*, MAX_NAMES + 1, mtInternal);
398     _perf_lock_wait_time = NEW_C_HEAP_ARRAY(PerfCounter*, MAX_NAMES + 1, mtInternal);
399     _perf_lock_hold_time = NEW_C_HEAP_ARRAY(PerfCounter*, MAX_NAMES + 1, mtInternal);
400 
401     NEWPERFEVENTCOUNTER(_perf_lock_count[0],     SUN_RT, PerfDataManager::counter_name("Other", "Count"));
402     NEWPERFEVENTCOUNTER(_perf_lock_wait_time[0], SUN_RT, PerfDataManager::counter_name("Other", "BeforeTime"));
403     NEWPERFEVENTCOUNTER(_perf_lock_hold_time[0], SUN_RT, PerfDataManager::counter_name("Other", "AfterTime"));
404     for (int i = 0; i < MAX_NAMES; i++) {
405       ResourceMark rm;
406       const char* counter_name = _names[i];
407       if (counter_name == nullptr) {
408         stringStream ss;
409         ss.print("UnnamedMutex#%d", i);
410         counter_name = ss.as_string();
411       }
412       NEWPERFEVENTCOUNTER(_perf_lock_count[i + 1],     SUN_RT, PerfDataManager::counter_name(counter_name, "Count"));
413       NEWPERFEVENTCOUNTER(_perf_lock_wait_time[i + 1], SUN_RT, PerfDataManager::counter_name(counter_name, "BeforeTime"));
414       NEWPERFEVENTCOUNTER(_perf_lock_hold_time[i + 1], SUN_RT, PerfDataManager::counter_name(counter_name, "AfterTime"));
415     }
416     if (HAS_PENDING_EXCEPTION) {
417       vm_exit_during_initialization("MutexLockerImpl::init_counters() failed unexpectedly");
418     }
419   }
420 }
421 
422 int MutexLockerImpl::name2id(const char* name) {
423   if (ProfileVMLocks && UsePerfData) {
424     for (int i = 0; i < _num_names; i++) {
425       if (strcmp(_names[i], name) == 0) {
426         _is_unique[i] = false;
427         return i;
428       }
429     }
430     if (_num_names < MAX_NAMES) {
431       int new_id = _num_names++;
432       _names[new_id] = os::strdup(name, mtInternal);
433       _is_unique[new_id] = true;
434       return new_id;
435     }
436     log_debug(init)("Unnamed: %s", name); // no slots left
437   }
438   return -1;
439 }
440 
441 void MutexLockerImpl::print_counter_on(outputStream* st, const char* name, bool is_unique, int idx) {
442   jlong count = _perf_lock_count[idx]->get_value();
443   if (count > 0) {
444     st->print_cr("  %3d: %s%40s = " JLONG_FORMAT_W(5) "us (" JLONG_FORMAT_W(5) "us) / " JLONG_FORMAT_W(9) " events",
445                  idx, (is_unique ? " " : "M"), name,
446                  Management::ticks_to_us(_perf_lock_hold_time[idx]->get_value()),
447                  Management::ticks_to_us(_perf_lock_wait_time[idx]->get_value()),
448                  count);
449   }
450 }
451 
452 static jlong accumulate_lock_counters(PerfCounter** lock_counters) {
453   jlong acc = 0;
454   for (int i = 0; i < _num_names + 1; i++) { // 0 slot is reserved for unnamed locks
455     if (lock_counters[i] == nullptr) {
456       break;
457     }
458     acc += lock_counters[i]->get_value();
459   }
460   return acc;
461 }
462 
463 void MutexLockerImpl::print_counters_on(outputStream* st) {
464   if (ProfileVMLocks && UsePerfData) {
465     jlong total_count     = accumulate_lock_counters(_perf_lock_count);
466     jlong total_wait_time = accumulate_lock_counters(_perf_lock_wait_time);
467     jlong total_hold_time = accumulate_lock_counters(_perf_lock_hold_time);
468 
469     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\"",
470                  Mutex::num_mutex(), _num_names,
471                  Management::ticks_to_us(total_hold_time),
472                  Management::ticks_to_us(total_wait_time),
473                  total_count);
474     for (int i = 0; i < _num_names; i++) {
475       print_counter_on(st, _names[i], _is_unique[i], i+1);
476     }
477     print_counter_on(st, "Unnamed / Other", false /*is_unique*/, 0);
478   } else {
479     st->print_cr("MutexLocker: no info (%s is disabled)", (UsePerfData ? "ProfileVMLocks" : "UsePerfData"));
480   }
481 }
482 
483 void MutexLockerImpl::post_initialize() {
484   // Print mutex ranks if requested.
485   LogTarget(Info, vmmutex) lt;
486   if (lt.is_enabled()) {
487     ResourceMark rm;
488     LogStream ls(lt);
489     Mutex::print_lock_ranks(&ls);
490   }
491 }
492 
493 GCMutexLocker::GCMutexLocker(Mutex* mutex) {
494   if (SafepointSynchronize::is_at_safepoint()) {
495     _locked = false;
496   } else {
497     _mutex = mutex;
498     _locked = true;
499     _mutex->lock();
500   }
501 }
502