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 #ifndef SHARE_RUNTIME_MUTEXLOCKER_HPP
26 #define SHARE_RUNTIME_MUTEXLOCKER_HPP
27
28 #include "memory/allocation.hpp"
29 #include "runtime/flags/flagSetting.hpp"
30 #include "runtime/mutex.hpp"
31
32 // Mutexes used in the VM.
33
34 extern Mutex* Patching_lock; // a lock used to guard code patching of compiled code
35 extern Mutex* NMethodState_lock; // a lock used to guard a compiled method state
36 extern Monitor* SystemDictionary_lock; // a lock on the system dictionary
37 extern Mutex* InvokeMethodTypeTable_lock;
38 extern Monitor* InvokeMethodIntrinsicTable_lock;
39 extern Mutex* SharedDictionary_lock; // a lock on the CDS shared dictionary
40 extern Monitor* ClassInitError_lock; // a lock on the class initialization error table
41 extern Mutex* Module_lock; // a lock on module and package related data structures
42 extern Mutex* CompiledIC_lock; // a lock used to guard compiled IC patching and access
43 extern Mutex* VMStatistic_lock; // a lock used to guard statistics count increment
44 extern Mutex* JmethodIdCreation_lock; // a lock on creating JNI method identifiers
45 extern Mutex* JfieldIdCreation_lock; // a lock on creating JNI static field identifiers
46 extern Monitor* JNICritical_lock; // a lock used while entering and exiting JNI critical regions, allows GC to sometimes get in
47 extern Mutex* JvmtiThreadState_lock; // a lock on modification of JVMTI thread data
48 extern Monitor* EscapeBarrier_lock; // a lock to sync reallocating and relocking objects because of JVMTI access
49 extern Monitor* JvmtiVTMSTransition_lock; // a lock for Virtual Thread Mount State transition (VTMS transition) management
50 extern Monitor* Heap_lock; // a lock on the heap
60 extern Monitor* CodeCache_lock; // a lock on the CodeCache
61 extern Mutex* TouchedMethodLog_lock; // a lock on allocation of LogExecutedMethods info
62 extern Mutex* RetData_lock; // a lock on installation of RetData inside method data
63 extern Monitor* VMOperation_lock; // a lock on queue of vm_operations waiting to execute
64 extern Monitor* Threads_lock; // a lock on the Threads table of active Java threads
65 // (also used by Safepoints too to block threads creation/destruction)
66 extern Mutex* NonJavaThreadsList_lock; // a lock on the NonJavaThreads list
67 extern Mutex* NonJavaThreadsListSync_lock; // a lock for NonJavaThreads list synchronization
68 extern Monitor* CGC_lock; // used for coordination between
69 // fore- & background GC threads.
70 extern Monitor* STS_lock; // used for joining/leaving SuspendibleThreadSet.
71 extern Monitor* G1OldGCCount_lock; // in support of "concurrent" full gc
72 extern Mutex* G1RareEvent_lock; // Synchronizes (rare) parallel GC operations.
73 extern Mutex* G1DetachedRefinementStats_lock; // Lock protecting detached refinement stats
74 extern Mutex* MarkStackFreeList_lock; // Protects access to the global mark stack free list.
75 extern Mutex* MarkStackChunkList_lock; // Protects access to the global mark stack chunk list.
76 extern Mutex* MonitoringSupport_lock; // Protects updates to the serviceability memory pools and allocated memory high water mark.
77 extern Monitor* ConcurrentGCBreakpoints_lock; // Protects concurrent GC breakpoint management
78 extern Mutex* Compile_lock; // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
79 extern Monitor* MethodCompileQueue_lock; // a lock held when method compilations are enqueued, dequeued
80 extern Monitor* CompileThread_lock; // a lock held by compile threads during compilation system initialization
81 extern Monitor* Compilation_lock; // a lock used to pause compilation
82 extern Mutex* CompileTaskAlloc_lock; // a lock held when CompileTasks are allocated
83 extern Mutex* CompileStatistics_lock; // a lock held when updating compilation statistics
84 extern Mutex* DirectivesStack_lock; // a lock held when mutating the dirstack and ref counting directives
85 extern Monitor* Terminator_lock; // a lock used to guard termination of the vm
86 extern Monitor* InitCompleted_lock; // a lock used to signal threads waiting on init completed
87 extern Monitor* BeforeExit_lock; // a lock used to guard cleanups and shutdown hooks
88 extern Monitor* Notify_lock; // a lock used to synchronize the start-up of the vm
89 extern Mutex* ExceptionCache_lock; // a lock used to synchronize exception cache updates
90
91 #ifndef PRODUCT
92 extern Mutex* FullGCALot_lock; // a lock to make FullGCALot MT safe
93 #endif // PRODUCT
94
95 extern Mutex* RawMonitor_lock;
96 extern Mutex* PerfDataMemAlloc_lock; // a lock on the allocator for PerfData memory for performance data
97 extern Mutex* PerfDataManager_lock; // a long on access to PerfDataManager resources
98
99 extern Mutex* FreeList_lock; // protects the free region list during safepoints
100 extern Mutex* OldSets_lock; // protects the old region sets
101 extern Mutex* Uncommit_lock; // protects the uncommit list when not at safepoints
108 extern Monitor* PeriodicTask_lock; // protects the periodic task structure
109 extern Monitor* RedefineClasses_lock; // locks classes from parallel redefinition
110 extern Mutex* Verify_lock; // synchronize initialization of verify library
111 extern Monitor* ThreadsSMRDelete_lock; // Used by ThreadsSMRSupport to take pressure off the Threads_lock
112 extern Mutex* ThreadIdTableCreate_lock; // Used by ThreadIdTable to lazily create the thread id table
113 extern Mutex* SharedDecoder_lock; // serializes access to the decoder during normal (not error reporting) use
114 extern Mutex* DCmdFactory_lock; // serialize access to DCmdFactory information
115 extern Mutex* NMTQuery_lock; // serialize NMT Dcmd queries
116 extern Mutex* NMTCompilationCostHistory_lock; // guards NMT compilation cost history
117 #if INCLUDE_CDS
118 #if INCLUDE_JVMTI
119 extern Mutex* CDSClassFileStream_lock; // FileMapInfo::open_stream_for_jvmti
120 #endif
121 extern Mutex* DumpTimeTable_lock; // SystemDictionaryShared::_dumptime_table
122 extern Mutex* CDSLambda_lock; // SystemDictionaryShared::get_shared_lambda_proxy_class
123 extern Mutex* DumpRegion_lock; // Symbol::operator new(size_t sz, int len)
124 extern Mutex* ClassListFile_lock; // ClassListWriter()
125 extern Mutex* UnregisteredClassesTable_lock; // UnregisteredClassesTableTable
126 extern Mutex* LambdaFormInvokers_lock; // Protecting LambdaFormInvokers::_lambdaform_lines
127 extern Mutex* ScratchObjects_lock; // Protecting _scratch_xxx_table in heapShared.cpp
128 #endif // INCLUDE_CDS
129 #if INCLUDE_JFR
130 extern Mutex* JfrStacktrace_lock; // used to guard access to the JFR stacktrace table
131 extern Monitor* JfrMsg_lock; // protects JFR messaging
132 extern Mutex* JfrBuffer_lock; // protects JFR buffer operations
133 extern Monitor* JfrThreadSampler_lock; // used to suspend/resume JFR thread sampler
134 #endif
135
136 extern Mutex* Metaspace_lock; // protects Metaspace virtualspace and chunk expansions
137 extern Monitor* MetaspaceCritical_lock; // synchronizes failed metaspace allocations that risk throwing metaspace OOM
138 extern Mutex* ClassLoaderDataGraph_lock; // protects CLDG list, needed for concurrent unloading
139
140
141 extern Mutex* CodeHeapStateAnalytics_lock; // lock print functions against concurrent analyze functions.
142 // Only used locally in PrintCodeCacheLayout processing.
143
144 extern Mutex* ExternalsRecorder_lock; // used to guard access to the external addresses table
145
146 extern Monitor* ContinuationRelativize_lock;
147
170
171 // Print all mutexes/monitors that are currently owned by a thread; called
172 // by fatal error handler.
173 void print_owned_locks_on_error(outputStream* st);
174 void print_lock_ranks(outputStream* st);
175
176 // for debugging: check that we're already owning this lock (or are at a safepoint / handshake)
177 #ifdef ASSERT
178 void assert_locked_or_safepoint(const Mutex* lock);
179 void assert_lock_strong(const Mutex* lock);
180 #else
181 #define assert_locked_or_safepoint(lock)
182 #define assert_lock_strong(lock)
183 #endif
184
185 // Internal implementation. Skips on null Mutex.
186 // Subclasses enforce stronger invariants.
187 class MutexLockerImpl: public StackObj {
188 protected:
189 Mutex* _mutex;
190
191 MutexLockerImpl(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
192 _mutex(mutex) {
193 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
194 if (_mutex != nullptr) {
195 if (no_safepoint_check) {
196 _mutex->lock_without_safepoint_check();
197 } else {
198 _mutex->lock();
199 }
200 }
201 }
202
203 MutexLockerImpl(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
204 _mutex(mutex) {
205 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
206 if (_mutex != nullptr) {
207 if (no_safepoint_check) {
208 _mutex->lock_without_safepoint_check(thread);
209 } else {
210 _mutex->lock(thread);
211 }
212 }
213 }
214
215 ~MutexLockerImpl() {
216 if (_mutex != nullptr) {
217 assert_lock_strong(_mutex);
218 _mutex->unlock();
219 }
220 }
221
222 public:
223 static void post_initialize();
224 };
225
226 // Simplest mutex locker.
227 // Does not allow null mutexes.
228 class MutexLocker: public MutexLockerImpl {
229 public:
230 MutexLocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
231 MutexLockerImpl(mutex, flag) {
232 assert(mutex != nullptr, "null mutex not allowed");
233 }
234
235 MutexLocker(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
236 MutexLockerImpl(thread, mutex, flag) {
237 assert(mutex != nullptr, "null mutex not allowed");
238 }
239 };
240
241 // Conditional mutex locker.
242 // Like MutexLocker above, but only locks when condition is true.
243 class ConditionalMutexLocker: public MutexLockerImpl {
|
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 #ifndef SHARE_RUNTIME_MUTEXLOCKER_HPP
26 #define SHARE_RUNTIME_MUTEXLOCKER_HPP
27
28 #include "logging/log.hpp"
29 #include "memory/allocation.hpp"
30 #include "runtime/flags/flagSetting.hpp"
31 #include "runtime/mutex.hpp"
32 #include "runtime/perfData.hpp"
33 #include "runtime/thread.hpp"
34
35 // Mutexes used in the VM.
36
37 extern Mutex* Patching_lock; // a lock used to guard code patching of compiled code
38 extern Mutex* NMethodState_lock; // a lock used to guard a compiled method state
39 extern Monitor* SystemDictionary_lock; // a lock on the system dictionary
40 extern Mutex* InvokeMethodTypeTable_lock;
41 extern Monitor* InvokeMethodIntrinsicTable_lock;
42 extern Mutex* SharedDictionary_lock; // a lock on the CDS shared dictionary
43 extern Monitor* ClassInitError_lock; // a lock on the class initialization error table
44 extern Mutex* Module_lock; // a lock on module and package related data structures
45 extern Mutex* CompiledIC_lock; // a lock used to guard compiled IC patching and access
46 extern Mutex* VMStatistic_lock; // a lock used to guard statistics count increment
47 extern Mutex* JmethodIdCreation_lock; // a lock on creating JNI method identifiers
48 extern Mutex* JfieldIdCreation_lock; // a lock on creating JNI static field identifiers
49 extern Monitor* JNICritical_lock; // a lock used while entering and exiting JNI critical regions, allows GC to sometimes get in
50 extern Mutex* JvmtiThreadState_lock; // a lock on modification of JVMTI thread data
51 extern Monitor* EscapeBarrier_lock; // a lock to sync reallocating and relocking objects because of JVMTI access
52 extern Monitor* JvmtiVTMSTransition_lock; // a lock for Virtual Thread Mount State transition (VTMS transition) management
53 extern Monitor* Heap_lock; // a lock on the heap
63 extern Monitor* CodeCache_lock; // a lock on the CodeCache
64 extern Mutex* TouchedMethodLog_lock; // a lock on allocation of LogExecutedMethods info
65 extern Mutex* RetData_lock; // a lock on installation of RetData inside method data
66 extern Monitor* VMOperation_lock; // a lock on queue of vm_operations waiting to execute
67 extern Monitor* Threads_lock; // a lock on the Threads table of active Java threads
68 // (also used by Safepoints too to block threads creation/destruction)
69 extern Mutex* NonJavaThreadsList_lock; // a lock on the NonJavaThreads list
70 extern Mutex* NonJavaThreadsListSync_lock; // a lock for NonJavaThreads list synchronization
71 extern Monitor* CGC_lock; // used for coordination between
72 // fore- & background GC threads.
73 extern Monitor* STS_lock; // used for joining/leaving SuspendibleThreadSet.
74 extern Monitor* G1OldGCCount_lock; // in support of "concurrent" full gc
75 extern Mutex* G1RareEvent_lock; // Synchronizes (rare) parallel GC operations.
76 extern Mutex* G1DetachedRefinementStats_lock; // Lock protecting detached refinement stats
77 extern Mutex* MarkStackFreeList_lock; // Protects access to the global mark stack free list.
78 extern Mutex* MarkStackChunkList_lock; // Protects access to the global mark stack chunk list.
79 extern Mutex* MonitoringSupport_lock; // Protects updates to the serviceability memory pools and allocated memory high water mark.
80 extern Monitor* ConcurrentGCBreakpoints_lock; // Protects concurrent GC breakpoint management
81 extern Mutex* Compile_lock; // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
82 extern Monitor* MethodCompileQueue_lock; // a lock held when method compilations are enqueued, dequeued
83 extern Monitor* MethodCompileQueueC1_lock; // a lock held when method compilations are enqueued, dequeued
84 extern Monitor* MethodCompileQueueC2_lock; // a lock held when method compilations are enqueued, dequeued
85 extern Monitor* MethodCompileQueueC3_lock; // a lock held when method compilations are enqueued, dequeued
86 extern Monitor* MethodCompileQueueSC1_lock; // a lock held when method compilations are enqueued, dequeued
87 extern Monitor* MethodCompileQueueSC2_lock; // a lock held when method compilations are enqueued, dequeued
88 extern Monitor* CompileThread_lock; // a lock held by compile threads during compilation system initialization
89 extern Monitor* Compilation_lock; // a lock used to pause compilation
90 extern Mutex* TrainingData_lock; // a lock used when accessing training records
91 extern Monitor* TrainingReplayQueue_lock; // a lock held when class are added/removed to the training replay queue
92 extern Mutex* CompileTaskAlloc_lock; // a lock held when CompileTasks are allocated
93 extern Mutex* CompileStatistics_lock; // a lock held when updating compilation statistics
94 extern Mutex* DirectivesStack_lock; // a lock held when mutating the dirstack and ref counting directives
95 extern Monitor* Terminator_lock; // a lock used to guard termination of the vm
96 extern Monitor* InitCompleted_lock; // a lock used to signal threads waiting on init completed
97 extern Monitor* BeforeExit_lock; // a lock used to guard cleanups and shutdown hooks
98 extern Monitor* Notify_lock; // a lock used to synchronize the start-up of the vm
99 extern Mutex* ExceptionCache_lock; // a lock used to synchronize exception cache updates
100
101 #ifndef PRODUCT
102 extern Mutex* FullGCALot_lock; // a lock to make FullGCALot MT safe
103 #endif // PRODUCT
104
105 extern Mutex* RawMonitor_lock;
106 extern Mutex* PerfDataMemAlloc_lock; // a lock on the allocator for PerfData memory for performance data
107 extern Mutex* PerfDataManager_lock; // a long on access to PerfDataManager resources
108
109 extern Mutex* FreeList_lock; // protects the free region list during safepoints
110 extern Mutex* OldSets_lock; // protects the old region sets
111 extern Mutex* Uncommit_lock; // protects the uncommit list when not at safepoints
118 extern Monitor* PeriodicTask_lock; // protects the periodic task structure
119 extern Monitor* RedefineClasses_lock; // locks classes from parallel redefinition
120 extern Mutex* Verify_lock; // synchronize initialization of verify library
121 extern Monitor* ThreadsSMRDelete_lock; // Used by ThreadsSMRSupport to take pressure off the Threads_lock
122 extern Mutex* ThreadIdTableCreate_lock; // Used by ThreadIdTable to lazily create the thread id table
123 extern Mutex* SharedDecoder_lock; // serializes access to the decoder during normal (not error reporting) use
124 extern Mutex* DCmdFactory_lock; // serialize access to DCmdFactory information
125 extern Mutex* NMTQuery_lock; // serialize NMT Dcmd queries
126 extern Mutex* NMTCompilationCostHistory_lock; // guards NMT compilation cost history
127 #if INCLUDE_CDS
128 #if INCLUDE_JVMTI
129 extern Mutex* CDSClassFileStream_lock; // FileMapInfo::open_stream_for_jvmti
130 #endif
131 extern Mutex* DumpTimeTable_lock; // SystemDictionaryShared::_dumptime_table
132 extern Mutex* CDSLambda_lock; // SystemDictionaryShared::get_shared_lambda_proxy_class
133 extern Mutex* DumpRegion_lock; // Symbol::operator new(size_t sz, int len)
134 extern Mutex* ClassListFile_lock; // ClassListWriter()
135 extern Mutex* UnregisteredClassesTable_lock; // UnregisteredClassesTableTable
136 extern Mutex* LambdaFormInvokers_lock; // Protecting LambdaFormInvokers::_lambdaform_lines
137 extern Mutex* ScratchObjects_lock; // Protecting _scratch_xxx_table in heapShared.cpp
138 extern Mutex* ArchivedObjectTables_lock; // Protecting the table used by HeapShared::get_archived_object_permanent_index()
139 #endif // INCLUDE_CDS
140 #if INCLUDE_JFR
141 extern Mutex* JfrStacktrace_lock; // used to guard access to the JFR stacktrace table
142 extern Monitor* JfrMsg_lock; // protects JFR messaging
143 extern Mutex* JfrBuffer_lock; // protects JFR buffer operations
144 extern Monitor* JfrThreadSampler_lock; // used to suspend/resume JFR thread sampler
145 #endif
146
147 extern Mutex* Metaspace_lock; // protects Metaspace virtualspace and chunk expansions
148 extern Monitor* MetaspaceCritical_lock; // synchronizes failed metaspace allocations that risk throwing metaspace OOM
149 extern Mutex* ClassLoaderDataGraph_lock; // protects CLDG list, needed for concurrent unloading
150
151
152 extern Mutex* CodeHeapStateAnalytics_lock; // lock print functions against concurrent analyze functions.
153 // Only used locally in PrintCodeCacheLayout processing.
154
155 extern Mutex* ExternalsRecorder_lock; // used to guard access to the external addresses table
156
157 extern Monitor* ContinuationRelativize_lock;
158
181
182 // Print all mutexes/monitors that are currently owned by a thread; called
183 // by fatal error handler.
184 void print_owned_locks_on_error(outputStream* st);
185 void print_lock_ranks(outputStream* st);
186
187 // for debugging: check that we're already owning this lock (or are at a safepoint / handshake)
188 #ifdef ASSERT
189 void assert_locked_or_safepoint(const Mutex* lock);
190 void assert_lock_strong(const Mutex* lock);
191 #else
192 #define assert_locked_or_safepoint(lock)
193 #define assert_lock_strong(lock)
194 #endif
195
196 // Internal implementation. Skips on null Mutex.
197 // Subclasses enforce stronger invariants.
198 class MutexLockerImpl: public StackObj {
199 protected:
200 Mutex* _mutex;
201 bool _prof;
202 elapsedTimer _before;
203 elapsedTimer _after;
204
205 private:
206 static PerfCounter** _perf_lock_count;
207 static PerfCounter** _perf_lock_wait_time;
208 static PerfCounter** _perf_lock_hold_time;
209
210 public:
211
212 MutexLockerImpl(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
213 _mutex(mutex), _prof(ProfileVMLocks && Thread::current_or_null() != nullptr && Thread::current()->profile_vm_locks()) {
214
215 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
216 if (_mutex != nullptr) {
217 if (_prof) { _before.start(); } // before
218
219 if (no_safepoint_check) {
220 _mutex->lock_without_safepoint_check();
221 } else {
222 _mutex->lock();
223 }
224
225 if (_prof) { _before.stop(); _after.start(); } // after
226 }
227 }
228
229 MutexLockerImpl(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
230 _mutex(mutex), _prof(thread->profile_vm_locks()) {
231
232 if (_prof) { _before.start(); } // before
233
234 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
235 if (_mutex != nullptr) {
236 if (no_safepoint_check) {
237 _mutex->lock_without_safepoint_check(thread);
238 } else {
239 _mutex->lock(thread);
240 }
241 }
242
243 if (_prof) { _before.stop(); _after.start(); } // after
244 }
245
246 ~MutexLockerImpl() {
247 if (_mutex != nullptr) {
248 assert_lock_strong(_mutex);
249 _mutex->unlock();
250
251 if (_mutex->id() == -1) {
252 log_trace(init)("Unnamed unclassified lock: %s", _mutex->name());
253 }
254
255 if (_prof) {
256 assert(UsePerfData, "required");
257 _after.stop();
258 _perf_lock_count [_mutex->id() + 1]->inc();
259 _perf_lock_wait_time[_mutex->id() + 1]->inc(_before.ticks());
260 _perf_lock_hold_time[_mutex->id() + 1]->inc(_after.ticks());
261 }
262 }
263 }
264
265 private:
266 static void print_counter_on(outputStream* st, const char* name, bool is_unique, int idx);
267
268 public:
269 static int name2id(const char* name);
270
271 static void post_initialize();
272 static void init_counters();
273 static void print_counters_on(outputStream* st);
274 };
275
276 // Simplest mutex locker.
277 // Does not allow null mutexes.
278 class MutexLocker: public MutexLockerImpl {
279 public:
280 MutexLocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
281 MutexLockerImpl(mutex, flag) {
282 assert(mutex != nullptr, "null mutex not allowed");
283 }
284
285 MutexLocker(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
286 MutexLockerImpl(thread, mutex, flag) {
287 assert(mutex != nullptr, "null mutex not allowed");
288 }
289 };
290
291 // Conditional mutex locker.
292 // Like MutexLocker above, but only locks when condition is true.
293 class ConditionalMutexLocker: public MutexLockerImpl {
|