Intel(R) Threading Building Blocks Doxygen Documentation  version 4.2.3
queuing_rw_mutex.h
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1 /*
2  Copyright (c) 2005-2019 Intel Corporation
3 
4  Licensed under the Apache License, Version 2.0 (the "License");
5  you may not use this file except in compliance with the License.
6  You may obtain a copy of the License at
7 
8  http://www.apache.org/licenses/LICENSE-2.0
9 
10  Unless required by applicable law or agreed to in writing, software
11  distributed under the License is distributed on an "AS IS" BASIS,
12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  See the License for the specific language governing permissions and
14  limitations under the License.
15 */
16 
17 #ifndef __TBB_queuing_rw_mutex_H
18 #define __TBB_queuing_rw_mutex_H
19 
20 #include <cstring>
21 #include "atomic.h"
22 #include "tbb_profiling.h"
23 
24 namespace tbb {
25 
27 
30 class queuing_rw_mutex : internal::mutex_copy_deprecated_and_disabled {
31 public:
34  q_tail = NULL;
35 #if TBB_USE_THREADING_TOOLS
37 #endif
38  }
39 
42 #if TBB_USE_ASSERT
43  __TBB_ASSERT( !q_tail, "destruction of an acquired mutex");
44 #endif
45  }
46 
48 
50  class scoped_lock: internal::no_copy {
52  void initialize() {
53  my_mutex = NULL;
54  my_internal_lock = 0;
55  my_going = 0;
56 #if TBB_USE_ASSERT
57  my_state = 0xFF; // Set to invalid state
60 #endif /* TBB_USE_ASSERT */
61  }
62 
63  public:
65 
67 
69  scoped_lock( queuing_rw_mutex& m, bool write=true ) {
70  initialize();
71  acquire(m,write);
72  }
73 
76  if( my_mutex ) release();
77  }
78 
80  void acquire( queuing_rw_mutex& m, bool write=true );
81 
83  bool try_acquire( queuing_rw_mutex& m, bool write=true );
84 
86  void release();
87 
89 
90  bool upgrade_to_writer();
91 
93  bool downgrade_to_reader();
94 
95  private:
98 
101 
102  typedef unsigned char state_t;
103 
106 
108 
109  unsigned char __TBB_atomic my_going;
110 
112  unsigned char my_internal_lock;
113 
115  void acquire_internal_lock();
116 
118 
120 
122  void release_internal_lock();
123 
126 
128  void unblock_or_wait_on_internal_lock( uintptr_t );
129  };
130 
132 
133  // Mutex traits
134  static const bool is_rw_mutex = true;
135  static const bool is_recursive_mutex = false;
136  static const bool is_fair_mutex = true;
137 
138 private:
141 
142 };
143 
145 
146 } // namespace tbb
147 
148 #endif /* __TBB_queuing_rw_mutex_H */
atomic< state_t > my_state
State of the request: reader, writer, active reader, other service states.
~scoped_lock()
Release lock (if lock is held).
scoped_lock *__TBB_atomic my_prev
The pointer to the previous and next competitors for a mutex.
bool downgrade_to_reader()
Downgrade writer to become a reader.
The scoped locking pattern.
~queuing_rw_mutex()
Destructor asserts if the mutex is acquired, i.e. q_tail is non-NULL.
void release_internal_lock()
Release the internal lock.
bool try_acquire_internal_lock()
Try to acquire the internal lock.
#define __TBB_EXPORTED_METHOD
Definition: tbb_stddef.h:98
queuing_rw_mutex * my_mutex
The pointer to the mutex owned, or NULL if not holding a mutex.
void initialize()
Initialize fields to mean "no lock held".
#define __TBB_ASSERT(predicate, comment)
No-op version of __TBB_ASSERT.
Definition: tbb_stddef.h:165
scoped_lock *__TBB_atomic *__TBB_atomic my_next
bool try_acquire(queuing_rw_mutex &m, bool write=true)
Acquire lock on given mutex if free (i.e. non-blocking)
void wait_for_release_of_internal_lock()
Wait for internal lock to be released.
Queuing reader-writer mutex with local-only spinning.
The graph class.
void unblock_or_wait_on_internal_lock(uintptr_t)
A helper function.
unsigned char __TBB_atomic my_going
The local spin-wait variable.
unsigned char my_internal_lock
A tiny internal lock.
static const bool is_recursive_mutex
atomic< scoped_lock * > q_tail
The last competitor requesting the lock.
void acquire(queuing_rw_mutex &m, bool write=true)
Acquire lock on given mutex.
static const bool is_fair_mutex
void __TBB_EXPORTED_METHOD internal_construct()
void poison_pointer(T *__TBB_atomic &)
Definition: tbb_stddef.h:305
scoped_lock(queuing_rw_mutex &m, bool write=true)
Acquire lock on given mutex.
#define __TBB_atomic
Definition: tbb_stddef.h:237
queuing_rw_mutex()
Construct unacquired mutex.
static const bool is_rw_mutex
scoped_lock()
Construct lock that has not acquired a mutex.
bool upgrade_to_writer()
Upgrade reader to become a writer.
void acquire_internal_lock()
Acquire the internal lock.
#define __TBB_DEFINE_PROFILING_SET_NAME(sync_object_type)

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