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 class Thread;
33
34 // Mutexes used in the VM.
35
36 extern Mutex* NMethodState_lock; // a lock used to guard a compiled method state
37 extern Monitor* SystemDictionary_lock; // a lock on the system dictionary
38 extern Mutex* InvokeMethodTypeTable_lock;
39 extern Monitor* InvokeMethodIntrinsicTable_lock;
40 extern Mutex* SharedDictionary_lock; // a lock on the CDS shared dictionary
41 extern Monitor* ClassInitError_lock; // a lock on the class initialization error table
42 extern Mutex* Module_lock; // a lock on module and package related data structures
43 extern Mutex* CompiledIC_lock; // a lock used to guard compiled IC patching and access
44 extern Mutex* VMStatistic_lock; // a lock used to guard statistics count increment
45 extern Mutex* JmethodIdCreation_lock; // a lock on creating JNI method identifiers
46 extern Mutex* JfieldIdCreation_lock; // a lock on creating JNI static field identifiers
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
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* ThreadsLockThrottle_lock; // used by Thread start/exit to reduce competition for Threads_lock,
65 // so a VM thread calling a safepoint is prioritized
66 extern Monitor* Threads_lock; // a lock on the Threads table of active Java threads
67 // (also used by Safepoints too to block threads creation/destruction)
68 extern Mutex* NonJavaThreadsList_lock; // a lock on the NonJavaThreads list
69 extern Mutex* NonJavaThreadsListSync_lock; // a lock for NonJavaThreads list synchronization
70 extern Monitor* CGC_lock; // used for coordination between
71 // fore- & background GC threads.
72 extern Monitor* STS_lock; // used for joining/leaving SuspendibleThreadSet.
73 extern Monitor* G1OldGCCount_lock; // in support of "concurrent" full gc
74 extern Mutex* G1RareEvent_lock; // Synchronizes (rare) parallel GC operations.
75 extern Mutex* G1DetachedRefinementStats_lock; // Lock protecting detached refinement stats
76 extern Mutex* MarkStackFreeList_lock; // Protects access to the global mark stack free list.
77 extern Mutex* MarkStackChunkList_lock; // Protects access to the global mark stack chunk list.
78 extern Mutex* MonitoringSupport_lock; // Protects updates to the serviceability memory pools and allocated memory high water mark.
79 extern Monitor* ConcurrentGCBreakpoints_lock; // Protects concurrent GC breakpoint management
80 extern Mutex* Compile_lock; // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
81 extern Monitor* MethodCompileQueue_lock; // a lock held when method compilations are enqueued, dequeued
82 extern Monitor* CompileThread_lock; // a lock held by compile threads during compilation system initialization
83 extern Monitor* Compilation_lock; // a lock used to pause compilation
84 extern Mutex* CompileTaskAlloc_lock; // a lock held when CompileTasks are allocated
85 extern Mutex* CompileStatistics_lock; // a lock held when updating compilation statistics
86 extern Mutex* DirectivesStack_lock; // a lock held when mutating the dirstack and ref counting directives
87 extern Monitor* Terminator_lock; // a lock used to guard termination of the vm
88 extern Monitor* InitCompleted_lock; // a lock used to signal threads waiting on init completed
89 extern Monitor* BeforeExit_lock; // a lock used to guard cleanups and shutdown hooks
90 extern Monitor* Notify_lock; // a lock used to synchronize the start-up of the vm
91 extern Mutex* ExceptionCache_lock; // a lock used to synchronize exception cache updates
92
93 #ifndef PRODUCT
94 extern Mutex* FullGCALot_lock; // a lock to make FullGCALot MT safe
95 #endif // PRODUCT
96
97 extern Mutex* RawMonitor_lock;
98 extern Mutex* PerfDataMemAlloc_lock; // a lock on the allocator for PerfData memory for performance data
99 extern Mutex* PerfDataManager_lock; // a long on access to PerfDataManager resources
100
101 extern Mutex* FreeList_lock; // protects the free region list during safepoints
102 extern Mutex* OldSets_lock; // protects the old region sets
103 extern Mutex* Uncommit_lock; // protects the uncommit list when not at safepoints
104 extern Monitor* RootRegionScan_lock; // used to notify that the CM threads have finished scanning the IM snapshot regions
111 extern Monitor* RedefineClasses_lock; // locks classes from parallel redefinition
112 extern Mutex* Verify_lock; // synchronize initialization of verify library
113 extern Monitor* ThreadsSMRDelete_lock; // Used by ThreadsSMRSupport to take pressure off the Threads_lock
114 extern Mutex* ThreadIdTableCreate_lock; // Used by ThreadIdTable to lazily create the thread id table
115 extern Mutex* SharedDecoder_lock; // serializes access to the decoder during normal (not error reporting) use
116 extern Mutex* DCmdFactory_lock; // serialize access to DCmdFactory information
117 extern Mutex* NMTQuery_lock; // serialize NMT Dcmd queries
118 extern Mutex* NMTCompilationCostHistory_lock; // guards NMT compilation cost history
119 extern Mutex* NmtVirtualMemory_lock; // guards NMT virtual memory updates
120 #if INCLUDE_CDS
121 #if INCLUDE_JVMTI
122 extern Mutex* CDSClassFileStream_lock; // FileMapInfo::open_stream_for_jvmti
123 #endif
124 extern Mutex* DumpTimeTable_lock; // SystemDictionaryShared::_dumptime_table
125 extern Mutex* CDSLambda_lock; // SystemDictionaryShared::get_shared_lambda_proxy_class
126 extern Mutex* DumpRegion_lock; // Symbol::operator new(size_t sz, int len)
127 extern Mutex* ClassListFile_lock; // ClassListWriter()
128 extern Mutex* UnregisteredClassesTable_lock; // UnregisteredClassesTableTable
129 extern Mutex* LambdaFormInvokers_lock; // Protecting LambdaFormInvokers::_lambdaform_lines
130 extern Mutex* ScratchObjects_lock; // Protecting _scratch_xxx_table in heapShared.cpp
131 #endif // INCLUDE_CDS
132 #if INCLUDE_JFR
133 extern Mutex* JfrStacktrace_lock; // used to guard access to the JFR stacktrace table
134 extern Monitor* JfrMsg_lock; // protects JFR messaging
135 extern Mutex* JfrBuffer_lock; // protects JFR buffer operations
136 extern Monitor* JfrThreadSampler_lock; // used to suspend/resume JFR thread sampler
137 #endif
138
139 extern Mutex* Metaspace_lock; // protects Metaspace virtualspace and chunk expansions
140 extern Monitor* MetaspaceCritical_lock; // synchronizes failed metaspace allocations that risk throwing metaspace OOM
141 extern Mutex* ClassLoaderDataGraph_lock; // protects CLDG list, needed for concurrent unloading
142
143
144 extern Mutex* CodeHeapStateAnalytics_lock; // lock print functions against concurrent analyze functions.
145 // Only used locally in PrintCodeCacheLayout processing.
146
147 extern Mutex* ExternalsRecorder_lock; // used to guard access to the external addresses table
148
149 extern Monitor* ContinuationRelativize_lock;
150
168 // See orderAccess.hpp. We assume throughout the VM that MutexLocker's
169 // and friends constructors do a fence, a lock and an acquire *in that
170 // order*. And that their destructors do a release and unlock, in *that*
171 // order. If their implementations change such that these assumptions
172 // are violated, a whole lot of code will break.
173
174 // for debugging: check that we're already owning this lock (or are at a safepoint / handshake)
175 #ifdef ASSERT
176 void assert_locked_or_safepoint(const Mutex* lock);
177 void assert_lock_strong(const Mutex* lock);
178 #else
179 #define assert_locked_or_safepoint(lock)
180 #define assert_lock_strong(lock)
181 #endif
182
183 // Internal implementation. Skips on null Mutex.
184 // Subclasses enforce stronger invariants.
185 class MutexLockerImpl: public StackObj {
186 protected:
187 Mutex* _mutex;
188
189 MutexLockerImpl(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
190 _mutex(mutex) {
191 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
192 if (_mutex != nullptr) {
193 if (no_safepoint_check) {
194 _mutex->lock_without_safepoint_check();
195 } else {
196 _mutex->lock();
197 }
198 }
199 }
200
201 MutexLockerImpl(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
202 _mutex(mutex) {
203 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
204 if (_mutex != nullptr) {
205 if (no_safepoint_check) {
206 _mutex->lock_without_safepoint_check(thread);
207 } else {
208 _mutex->lock(thread);
209 }
210 }
211 }
212
213 ~MutexLockerImpl() {
214 if (_mutex != nullptr) {
215 assert_lock_strong(_mutex);
216 _mutex->unlock();
217 }
218 }
219
220 public:
221 static void post_initialize();
222 };
223
224 // Simplest mutex locker.
225 // Does not allow null mutexes.
226 class MutexLocker: public MutexLockerImpl {
227 public:
228 MutexLocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
229 MutexLockerImpl(mutex, flag) {
230 assert(mutex != nullptr, "null mutex not allowed");
231 }
232
233 MutexLocker(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
234 MutexLockerImpl(thread, mutex, flag) {
235 assert(mutex != nullptr, "null mutex not allowed");
236 }
237 };
238
239 // Conditional mutex locker.
240 // Like MutexLocker above, but only locks when condition is true.
241 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 class Thread;
36
37 // Mutexes used in the VM.
38
39 extern Mutex* NMethodState_lock; // a lock used to guard a compiled method state
40 extern Monitor* SystemDictionary_lock; // a lock on the system dictionary
41 extern Mutex* InvokeMethodTypeTable_lock;
42 extern Monitor* InvokeMethodIntrinsicTable_lock;
43 extern Mutex* SharedDictionary_lock; // a lock on the CDS shared dictionary
44 extern Monitor* ClassInitError_lock; // a lock on the class initialization error table
45 extern Mutex* Module_lock; // a lock on module and package related data structures
46 extern Mutex* CompiledIC_lock; // a lock used to guard compiled IC patching and access
47 extern Mutex* VMStatistic_lock; // a lock used to guard statistics count increment
48 extern Mutex* JmethodIdCreation_lock; // a lock on creating JNI method identifiers
49 extern Mutex* JfieldIdCreation_lock; // a lock on creating JNI static field identifiers
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
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* ThreadsLockThrottle_lock; // used by Thread start/exit to reduce competition for Threads_lock,
68 // so a VM thread calling a safepoint is prioritized
69 extern Monitor* Threads_lock; // a lock on the Threads table of active Java threads
70 // (also used by Safepoints too to block threads creation/destruction)
71 extern Mutex* NonJavaThreadsList_lock; // a lock on the NonJavaThreads list
72 extern Mutex* NonJavaThreadsListSync_lock; // a lock for NonJavaThreads list synchronization
73 extern Monitor* CGC_lock; // used for coordination between
74 // fore- & background GC threads.
75 extern Monitor* STS_lock; // used for joining/leaving SuspendibleThreadSet.
76 extern Monitor* G1OldGCCount_lock; // in support of "concurrent" full gc
77 extern Mutex* G1RareEvent_lock; // Synchronizes (rare) parallel GC operations.
78 extern Mutex* G1DetachedRefinementStats_lock; // Lock protecting detached refinement stats
79 extern Mutex* MarkStackFreeList_lock; // Protects access to the global mark stack free list.
80 extern Mutex* MarkStackChunkList_lock; // Protects access to the global mark stack chunk list.
81 extern Mutex* MonitoringSupport_lock; // Protects updates to the serviceability memory pools and allocated memory high water mark.
82 extern Monitor* ConcurrentGCBreakpoints_lock; // Protects concurrent GC breakpoint management
83 extern Mutex* Compile_lock; // a lock held when Compilation is updating code (used to block CodeCache traversal, CHA updates, etc)
84 extern Monitor* MethodCompileQueue_lock; // a lock held when method compilations are enqueued, dequeued
85 extern Monitor* MethodCompileQueueC1_lock; // a lock held when method compilations are enqueued, dequeued
86 extern Monitor* MethodCompileQueueC2_lock; // a lock held when method compilations are enqueued, dequeued
87 extern Monitor* MethodCompileQueueC3_lock; // a lock held when method compilations are enqueued, dequeued
88 extern Monitor* MethodCompileQueueSC1_lock; // a lock held when method compilations are enqueued, dequeued
89 extern Monitor* MethodCompileQueueSC2_lock; // a lock held when method compilations are enqueued, dequeued
90 extern Monitor* CompileThread_lock; // a lock held by compile threads during compilation system initialization
91 extern Monitor* Compilation_lock; // a lock used to pause compilation
92 extern Mutex* TrainingData_lock; // a lock used when accessing training records
93 extern Monitor* TrainingReplayQueue_lock; // a lock held when class are added/removed to the training replay queue
94 extern Monitor* CompileTaskAlloc_lock; // a lock held when CompileTasks are allocated
95 extern Mutex* CompileStatistics_lock; // a lock held when updating compilation statistics
96 extern Mutex* DirectivesStack_lock; // a lock held when mutating the dirstack and ref counting directives
97 extern Monitor* Terminator_lock; // a lock used to guard termination of the vm
98 extern Monitor* InitCompleted_lock; // a lock used to signal threads waiting on init completed
99 extern Monitor* BeforeExit_lock; // a lock used to guard cleanups and shutdown hooks
100 extern Monitor* Notify_lock; // a lock used to synchronize the start-up of the vm
101 extern Mutex* ExceptionCache_lock; // a lock used to synchronize exception cache updates
102
103 #ifndef PRODUCT
104 extern Mutex* FullGCALot_lock; // a lock to make FullGCALot MT safe
105 #endif // PRODUCT
106
107 extern Mutex* RawMonitor_lock;
108 extern Mutex* PerfDataMemAlloc_lock; // a lock on the allocator for PerfData memory for performance data
109 extern Mutex* PerfDataManager_lock; // a long on access to PerfDataManager resources
110
111 extern Mutex* FreeList_lock; // protects the free region list during safepoints
112 extern Mutex* OldSets_lock; // protects the old region sets
113 extern Mutex* Uncommit_lock; // protects the uncommit list when not at safepoints
114 extern Monitor* RootRegionScan_lock; // used to notify that the CM threads have finished scanning the IM snapshot regions
121 extern Monitor* RedefineClasses_lock; // locks classes from parallel redefinition
122 extern Mutex* Verify_lock; // synchronize initialization of verify library
123 extern Monitor* ThreadsSMRDelete_lock; // Used by ThreadsSMRSupport to take pressure off the Threads_lock
124 extern Mutex* ThreadIdTableCreate_lock; // Used by ThreadIdTable to lazily create the thread id table
125 extern Mutex* SharedDecoder_lock; // serializes access to the decoder during normal (not error reporting) use
126 extern Mutex* DCmdFactory_lock; // serialize access to DCmdFactory information
127 extern Mutex* NMTQuery_lock; // serialize NMT Dcmd queries
128 extern Mutex* NMTCompilationCostHistory_lock; // guards NMT compilation cost history
129 extern Mutex* NmtVirtualMemory_lock; // guards NMT virtual memory updates
130 #if INCLUDE_CDS
131 #if INCLUDE_JVMTI
132 extern Mutex* CDSClassFileStream_lock; // FileMapInfo::open_stream_for_jvmti
133 #endif
134 extern Mutex* DumpTimeTable_lock; // SystemDictionaryShared::_dumptime_table
135 extern Mutex* CDSLambda_lock; // SystemDictionaryShared::get_shared_lambda_proxy_class
136 extern Mutex* DumpRegion_lock; // Symbol::operator new(size_t sz, int len)
137 extern Mutex* ClassListFile_lock; // ClassListWriter()
138 extern Mutex* UnregisteredClassesTable_lock; // UnregisteredClassesTableTable
139 extern Mutex* LambdaFormInvokers_lock; // Protecting LambdaFormInvokers::_lambdaform_lines
140 extern Mutex* ScratchObjects_lock; // Protecting _scratch_xxx_table in heapShared.cpp
141 extern Mutex* ArchivedObjectTables_lock; // Protecting the table used by HeapShared::get_archived_object_permanent_index()
142 #endif // INCLUDE_CDS
143 #if INCLUDE_JFR
144 extern Mutex* JfrStacktrace_lock; // used to guard access to the JFR stacktrace table
145 extern Monitor* JfrMsg_lock; // protects JFR messaging
146 extern Mutex* JfrBuffer_lock; // protects JFR buffer operations
147 extern Monitor* JfrThreadSampler_lock; // used to suspend/resume JFR thread sampler
148 #endif
149
150 extern Mutex* Metaspace_lock; // protects Metaspace virtualspace and chunk expansions
151 extern Monitor* MetaspaceCritical_lock; // synchronizes failed metaspace allocations that risk throwing metaspace OOM
152 extern Mutex* ClassLoaderDataGraph_lock; // protects CLDG list, needed for concurrent unloading
153
154
155 extern Mutex* CodeHeapStateAnalytics_lock; // lock print functions against concurrent analyze functions.
156 // Only used locally in PrintCodeCacheLayout processing.
157
158 extern Mutex* ExternalsRecorder_lock; // used to guard access to the external addresses table
159
160 extern Monitor* ContinuationRelativize_lock;
161
179 // See orderAccess.hpp. We assume throughout the VM that MutexLocker's
180 // and friends constructors do a fence, a lock and an acquire *in that
181 // order*. And that their destructors do a release and unlock, in *that*
182 // order. If their implementations change such that these assumptions
183 // are violated, a whole lot of code will break.
184
185 // for debugging: check that we're already owning this lock (or are at a safepoint / handshake)
186 #ifdef ASSERT
187 void assert_locked_or_safepoint(const Mutex* lock);
188 void assert_lock_strong(const Mutex* lock);
189 #else
190 #define assert_locked_or_safepoint(lock)
191 #define assert_lock_strong(lock)
192 #endif
193
194 // Internal implementation. Skips on null Mutex.
195 // Subclasses enforce stronger invariants.
196 class MutexLockerImpl: public StackObj {
197 protected:
198 Mutex* _mutex;
199 bool _prof;
200 elapsedTimer _before;
201 elapsedTimer _after;
202
203 private:
204 static PerfCounter** _perf_lock_count;
205 static PerfCounter** _perf_lock_wait_time;
206 static PerfCounter** _perf_lock_hold_time;
207
208 public:
209
210 MutexLockerImpl(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
211 _mutex(mutex), _prof(ProfileVMLocks && Thread::current_or_null() != nullptr && Thread::current()->profile_vm_locks()) {
212
213 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
214 if (_mutex != nullptr) {
215 if (_prof) { _before.start(); } // before
216
217 if (no_safepoint_check) {
218 _mutex->lock_without_safepoint_check();
219 } else {
220 _mutex->lock();
221 }
222
223 if (_prof) { _before.stop(); _after.start(); } // after
224 }
225 }
226
227 MutexLockerImpl(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
228 _mutex(mutex), _prof(thread->profile_vm_locks()) {
229
230 if (_prof) { _before.start(); } // before
231
232 bool no_safepoint_check = flag == Mutex::_no_safepoint_check_flag;
233 if (_mutex != nullptr) {
234 if (no_safepoint_check) {
235 _mutex->lock_without_safepoint_check(thread);
236 } else {
237 _mutex->lock(thread);
238 }
239 }
240
241 if (_prof) { _before.stop(); _after.start(); } // after
242 }
243
244 ~MutexLockerImpl() {
245 if (_mutex != nullptr) {
246 assert_lock_strong(_mutex);
247 _mutex->unlock();
248
249 if (_mutex->id() == -1) {
250 log_trace(init)("Unnamed unclassified lock: %s", _mutex->name());
251 }
252
253 if (_prof) {
254 assert(UsePerfData, "required");
255 _after.stop();
256 _perf_lock_count [_mutex->id() + 1]->inc();
257 _perf_lock_wait_time[_mutex->id() + 1]->inc(_before.ticks());
258 _perf_lock_hold_time[_mutex->id() + 1]->inc(_after.ticks());
259 }
260 }
261 }
262
263 private:
264 static void print_counter_on(outputStream* st, const char* name, bool is_unique, int idx);
265
266 public:
267 static int name2id(const char* name);
268
269 static void post_initialize();
270 static void init_counters();
271 static void print_counters_on(outputStream* st);
272 };
273
274 // Simplest mutex locker.
275 // Does not allow null mutexes.
276 class MutexLocker: public MutexLockerImpl {
277 public:
278 MutexLocker(Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
279 MutexLockerImpl(mutex, flag) {
280 assert(mutex != nullptr, "null mutex not allowed");
281 }
282
283 MutexLocker(Thread* thread, Mutex* mutex, Mutex::SafepointCheckFlag flag = Mutex::_safepoint_check_flag) :
284 MutexLockerImpl(thread, mutex, flag) {
285 assert(mutex != nullptr, "null mutex not allowed");
286 }
287 };
288
289 // Conditional mutex locker.
290 // Like MutexLocker above, but only locks when condition is true.
291 class ConditionalMutexLocker: public MutexLockerImpl {
|