Intel(R) Threading Building Blocks Doxygen Documentation  version 4.2.3
queuing_rw_mutex.h
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1 /*
2  Copyright (c) 2005-2020 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 #define __TBB_queuing_rw_mutex_H_include_area
22 
23 #include <cstring>
24 #include "atomic.h"
25 #include "tbb_profiling.h"
26 
27 namespace tbb {
28 
30 
34 public:
37  q_tail = NULL;
38 #if TBB_USE_THREADING_TOOLS
40 #endif
41  }
42 
45 #if TBB_USE_ASSERT
46  __TBB_ASSERT( !q_tail, "destruction of an acquired mutex");
47 #endif
48  }
49 
51 
55  void initialize() {
56  my_mutex = NULL;
57  my_internal_lock = 0;
58  my_going = 0;
59 #if TBB_USE_ASSERT
60  my_state = 0xFF; // Set to invalid state
63 #endif /* TBB_USE_ASSERT */
64  }
65 
66  public:
68 
70 
72  scoped_lock( queuing_rw_mutex& m, bool write=true ) {
73  initialize();
74  acquire(m,write);
75  }
76 
79  if( my_mutex ) release();
80  }
81 
83  void acquire( queuing_rw_mutex& m, bool write=true );
84 
86  bool try_acquire( queuing_rw_mutex& m, bool write=true );
87 
89  void release();
90 
92 
93  bool upgrade_to_writer();
94 
96  bool downgrade_to_reader();
97 
98  private:
101 
104 
105  typedef unsigned char state_t;
106 
108  atomic<state_t> my_state;
109 
111 
112  unsigned char __TBB_atomic my_going;
113 
115  unsigned char my_internal_lock;
116 
118  void acquire_internal_lock();
119 
121 
123 
125  void release_internal_lock();
126 
129 
131  void unblock_or_wait_on_internal_lock( uintptr_t );
132  };
133 
135 
136  // Mutex traits
137  static const bool is_rw_mutex = true;
138  static const bool is_recursive_mutex = false;
139  static const bool is_fair_mutex = true;
140 
141 private:
143  atomic<scoped_lock*> q_tail;
144 
145 };
146 
148 
149 } // namespace tbb
150 
152 #undef __TBB_queuing_rw_mutex_H_include_area
153 
154 #endif /* __TBB_queuing_rw_mutex_H */
bool upgrade_to_writer()
Upgrade reader to become a writer.
~scoped_lock()
Release lock (if lock is held).
void release_internal_lock()
Release the internal lock.
scoped_lock()
Construct lock that has not acquired a mutex.
#define __TBB_DEFINE_PROFILING_SET_NAME(sync_object_type)
void initialize()
Initialize fields to mean "no lock held".
~queuing_rw_mutex()
Destructor asserts if the mutex is acquired, i.e. q_tail is non-NULL.
void __TBB_EXPORTED_METHOD internal_construct()
The scoped locking pattern.
Base class for types that should not be copied or assigned.
Definition: tbb_stddef.h:330
scoped_lock *__TBB_atomic my_prev
The pointer to the previous and next competitors for a mutex.
bool try_acquire(queuing_rw_mutex &m, bool write=true)
Acquire lock on given mutex if free (i.e. non-blocking)
static const bool is_rw_mutex
atomic< state_t > my_state
State of the request: reader, writer, active reader, other service states.
unsigned char __TBB_atomic my_going
The local spin-wait variable.
bool downgrade_to_reader()
Downgrade writer to become a reader.
void acquire_internal_lock()
Acquire the internal lock.
#define __TBB_atomic
Definition: tbb_stddef.h:237
static const bool is_fair_mutex
Queuing reader-writer mutex with local-only spinning.
void unblock_or_wait_on_internal_lock(uintptr_t)
A helper function.
unsigned char my_internal_lock
A tiny internal lock.
static const bool is_recursive_mutex
#define __TBB_EXPORTED_METHOD
Definition: tbb_stddef.h:98
bool try_acquire_internal_lock()
Try to acquire the internal lock.
#define __TBB_ASSERT(predicate, comment)
No-op version of __TBB_ASSERT.
Definition: tbb_stddef.h:165
void wait_for_release_of_internal_lock()
Wait for internal lock to be released.
void poison_pointer(T *__TBB_atomic &)
Definition: tbb_stddef.h:305
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.
queuing_rw_mutex()
Construct unacquired mutex.
The graph class.
scoped_lock(queuing_rw_mutex &m, bool write=true)
Acquire lock on given mutex.
queuing_rw_mutex * my_mutex
The pointer to the mutex owned, or NULL if not holding a mutex.
scoped_lock *__TBB_atomic *__TBB_atomic my_next

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