ceph/src/boost/boost/log/detail/adaptive_mutex.hpp

   1 /*
   2  *          Copyright Andrey Semashev 2007 - 2015.
   3  * Distributed under the Boost Software License, Version 1.0.
   4  *    (See accompanying file LICENSE_1_0.txt or copy at
   5  *          http://www.boost.org/LICENSE_1_0.txt)
   6  */
   7 /*!
   8  * \file   adaptive_mutex.hpp
   9  * \author Andrey Semashev
  10  * \date   01.08.2010
  11  *
  12  * \brief  This header is the Boost.Log library implementation, see the library documentation
  13  *         at http://www.boost.org/doc/libs/release/libs/log/doc/html/index.html.
  14  */
  15
  16 #ifndef BOOST_LOG_DETAIL_ADAPTIVE_MUTEX_HPP_INCLUDED_
  17 #define BOOST_LOG_DETAIL_ADAPTIVE_MUTEX_HPP_INCLUDED_
  18
  19 #include <boost/log/detail/config.hpp>
  20
  21 #ifdef BOOST_HAS_PRAGMA_ONCE
  22 #pragma once
  23 #endif
  24
  25 #ifndef BOOST_LOG_NO_THREADS
  26
  27 #include <boost/throw_exception.hpp>
  28 #include <boost/thread/exceptions.hpp>
  29
  30 #if defined(BOOST_THREAD_POSIX) // This one can be defined by users, so it should go first
  31 #define BOOST_LOG_ADAPTIVE_MUTEX_USE_PTHREAD
  32 #elif defined(BOOST_WINDOWS)
  33 #define BOOST_LOG_ADAPTIVE_MUTEX_USE_WINAPI
  34 #elif defined(BOOST_HAS_PTHREADS)
  35 #define BOOST_LOG_ADAPTIVE_MUTEX_USE_PTHREAD
  36 #endif
  37
  38 #if defined(BOOST_LOG_ADAPTIVE_MUTEX_USE_WINAPI)
  39
  40 #include <boost/log/detail/pause.hpp>
  41 #include <boost/winapi/thread.hpp>
  42 #include <boost/detail/interlocked.hpp>
  43
  44 #if defined(__INTEL_COMPILER) || defined(_MSC_VER)
  45 #    if defined(__INTEL_COMPILER)
  46 #        define BOOST_LOG_COMPILER_BARRIER __memory_barrier()
  47 #    else
  48 extern "C" void _ReadWriteBarrier(void);
  49 #        if defined(BOOST_MSVC)
  50 #            pragma intrinsic(_ReadWriteBarrier)
  51 #        endif
  52 #        define BOOST_LOG_COMPILER_BARRIER _ReadWriteBarrier()
  53 #    endif
  54 #elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
  55 #    define BOOST_LOG_COMPILER_BARRIER __asm__ __volatile__("" : : : "memory")
  56 #endif
  57
  58 #include <boost/log/detail/header.hpp>
  59
  60 namespace boost {
  61
  62 BOOST_LOG_OPEN_NAMESPACE
  63
  64 namespace aux {
  65
  66 //! A mutex that performs spinning or thread yielding in case of contention
  67 class adaptive_mutex
  68 {
  69 private:
  70     enum state
  71     {
  72         initial_pause = 2,
  73         max_pause = 16
  74     };
  75
  76     long m_State;
  77
  78 public:
  79     adaptive_mutex() : m_State(0) {}
  80
  81     bool try_lock()
  82     {
  83         return (BOOST_INTERLOCKED_COMPARE_EXCHANGE(&m_State, 1L, 0L) == 0L);
  84     }
  85
  86     void lock()
  87     {
  88 #if defined(BOOST_LOG_AUX_PAUSE)
  89         unsigned int pause_count = initial_pause;
  90 #endif
  91         while (!try_lock())
  92         {
  93 #if defined(BOOST_LOG_AUX_PAUSE)
  94             if (pause_count < max_pause)
  95             {
  96                 for (unsigned int i = 0; i < pause_count; ++i)
  97                 {
  98                     BOOST_LOG_AUX_PAUSE;
  99                 }
 100                 pause_count += pause_count;
 101             }
 102             else
 103             {
 104                 // Restart spinning after waking up this thread
 105                 pause_count = initial_pause;
 106                 boost::winapi::SwitchToThread();
 107             }
 108 #else
 109             boost::winapi::SwitchToThread();
 110 #endif
 111         }
 112     }
 113
 114     void unlock()
 115     {
 116 #if (defined(_M_IX86) || defined(_M_AMD64)) && defined(BOOST_LOG_COMPILER_BARRIER)
 117         BOOST_LOG_COMPILER_BARRIER;
 118         m_State = 0L;
 119         BOOST_LOG_COMPILER_BARRIER;
 120 #else
 121         BOOST_INTERLOCKED_EXCHANGE(&m_State, 0L);
 122 #endif
 123     }
 124
 125     //  Non-copyable
 126     BOOST_DELETED_FUNCTION(adaptive_mutex(adaptive_mutex const&))
 127     BOOST_DELETED_FUNCTION(adaptive_mutex& operator= (adaptive_mutex const&))
 128 };
 129
 130 #undef BOOST_LOG_AUX_PAUSE
 131 #undef BOOST_LOG_COMPILER_BARRIER
 132
 133 } // namespace aux
 134
 135 BOOST_LOG_CLOSE_NAMESPACE // namespace log
 136
 137 } // namespace boost
 138
 139 #include <boost/log/detail/footer.hpp>
 140
 141 #elif defined(BOOST_LOG_ADAPTIVE_MUTEX_USE_PTHREAD)
 142
 143 #include <pthread.h>
 144 #include <boost/assert.hpp>
 145 #include <boost/log/detail/header.hpp>
 146
 147 #if defined(PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP)
 148 #define BOOST_LOG_ADAPTIVE_MUTEX_USE_PTHREAD_MUTEX_ADAPTIVE_NP
 149 #endif
 150
 151 namespace boost {
 152
 153 BOOST_LOG_OPEN_NAMESPACE
 154
 155 namespace aux {
 156
 157 //! A mutex that performs spinning or thread yielding in case of contention
 158 class adaptive_mutex
 159 {
 160 private:
 161     pthread_mutex_t m_State;
 162
 163 public:
 164     adaptive_mutex()
 165     {
 166 #if defined(BOOST_LOG_ADAPTIVE_MUTEX_USE_PTHREAD_MUTEX_ADAPTIVE_NP)
 167         pthread_mutexattr_t attrs;
 168         pthread_mutexattr_init(&attrs);
 169         pthread_mutexattr_settype(&attrs, PTHREAD_MUTEX_ADAPTIVE_NP);
 170
 171         const int err = pthread_mutex_init(&m_State, &attrs);
 172         pthread_mutexattr_destroy(&attrs);
 173 #else
 174         const int err = pthread_mutex_init(&m_State, NULL);
 175 #endif
 176         if (BOOST_UNLIKELY(err != 0))
 177             throw_exception< thread_resource_error >(err, "Failed to initialize an adaptive mutex", "adaptive_mutex::adaptive_mutex()", __FILE__, __LINE__);
 178     }
 179
 180     ~adaptive_mutex()
 181     {
 182         BOOST_VERIFY(pthread_mutex_destroy(&m_State) == 0);
 183     }
 184
 185     bool try_lock()
 186     {
 187         const int err = pthread_mutex_trylock(&m_State);
 188         if (err == 0)
 189             return true;
 190         if (BOOST_UNLIKELY(err != EBUSY))
 191             throw_exception< lock_error >(err, "Failed to lock an adaptive mutex", "adaptive_mutex::try_lock()", __FILE__, __LINE__);
 192         return false;
 193     }
 194
 195     void lock()
 196     {
 197         const int err = pthread_mutex_lock(&m_State);
 198         if (BOOST_UNLIKELY(err != 0))
 199             throw_exception< lock_error >(err, "Failed to lock an adaptive mutex", "adaptive_mutex::lock()", __FILE__, __LINE__);
 200     }
 201
 202     void unlock()
 203     {
 204         BOOST_VERIFY(pthread_mutex_unlock(&m_State) == 0);
 205     }
 206
 207     //  Non-copyable
 208     BOOST_DELETED_FUNCTION(adaptive_mutex(adaptive_mutex const&))
 209     BOOST_DELETED_FUNCTION(adaptive_mutex& operator= (adaptive_mutex const&))
 210
 211 private:
 212     template< typename ExceptionT >
 213     static BOOST_NOINLINE BOOST_LOG_NORETURN void throw_exception(int err, const char* descr, const char* func, const char* file, int line)
 214     {
 215 #if !defined(BOOST_EXCEPTION_DISABLE)
 216         boost::exception_detail::throw_exception_(ExceptionT(err, descr), func, file, line);
 217 #else
 218         boost::throw_exception(ExceptionT(err, descr));
 219 #endif
 220     }
 221 };
 222
 223 } // namespace aux
 224
 225 BOOST_LOG_CLOSE_NAMESPACE // namespace log
 226
 227 } // namespace boost
 228
 229 #include <boost/log/detail/footer.hpp>
 230
 231 #endif
 232
 233 #endif // BOOST_LOG_NO_THREADS
 234
 235 #endif // BOOST_LOG_DETAIL_ADAPTIVE_MUTEX_HPP_INCLUDED_