ceph/src/boost/libs/atomic/src/wait_on_address.cpp

   1 /*
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * Copyright (c) 2020 Andrey Semashev
   7  */
   8 /*!
   9  * \file   wait_on_address.cpp
  10  *
  11  * This file contains implementation of runtime detection of \c WaitOnAddress and related APIs on Windows.
  12  *
  13  * https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-waitonaddress
  14  * https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-wakebyaddresssingle
  15  * https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-wakebyaddressall
  16  */
  17
  18 // Include boost/winapi/config.hpp first to make sure target Windows version is selected by Boost.WinAPI
  19 #include <boost/winapi/config.hpp>
  20
  21 #include <boost/winapi/basic_types.hpp>
  22
  23 #include <boost/atomic/detail/config.hpp>
  24 #include <boost/atomic/detail/link.hpp>
  25 #include <boost/atomic/detail/once_flag.hpp>
  26 #include <boost/atomic/detail/wait_on_address.hpp>
  27
  28 #if BOOST_WINAPI_PARTITION_DESKTOP || BOOST_WINAPI_PARTITION_SYSTEM
  29
  30 #include <boost/static_assert.hpp>
  31 #include <boost/memory_order.hpp>
  32 #include <boost/winapi/thread.hpp>
  33 #include <boost/winapi/get_proc_address.hpp>
  34 #include <boost/winapi/dll.hpp>
  35
  36 #include <boost/atomic/detail/core_operations.hpp>
  37
  38 #endif // BOOST_WINAPI_PARTITION_DESKTOP || BOOST_WINAPI_PARTITION_SYSTEM
  39
  40 #include <boost/atomic/detail/header.hpp>
  41
  42 namespace boost {
  43 namespace atomics {
  44 namespace detail {
  45
  46 BOOST_ATOMIC_DECL wait_on_address_t* wait_on_address = NULL;
  47 BOOST_ATOMIC_DECL wake_by_address_t* wake_by_address_single = NULL;
  48 BOOST_ATOMIC_DECL wake_by_address_t* wake_by_address_all = NULL;
  49
  50 #if BOOST_WINAPI_PARTITION_DESKTOP || BOOST_WINAPI_PARTITION_SYSTEM
  51
  52 BOOST_ATOMIC_DECL once_flag wait_functions_once_flag = { 2u };
  53
  54 BOOST_ATOMIC_DECL void initialize_wait_functions() BOOST_NOEXCEPT
  55 {
  56     BOOST_STATIC_ASSERT_MSG(once_flag_operations::is_always_lock_free, "Boost.Atomic unsupported target platform: native atomic operations not implemented for bytes");
  57
  58     once_flag_operations::storage_type old_val = once_flag_operations::load(wait_functions_once_flag.m_flag, boost::memory_order_acquire);
  59     while (true)
  60     {
  61         if (old_val == 2u)
  62         {
  63             if (BOOST_UNLIKELY(!once_flag_operations::compare_exchange_strong(wait_functions_once_flag.m_flag, old_val, 1u, boost::memory_order_relaxed, boost::memory_order_relaxed)))
  64                 continue;
  65
  66             boost::winapi::HMODULE_ kernel_base = boost::winapi::get_module_handle(L"api-ms-win-core-synch-l1-2-0.dll");
  67             if (BOOST_LIKELY(kernel_base != NULL))
  68             {
  69                 wait_on_address_t* woa = (wait_on_address_t*)boost::winapi::get_proc_address(kernel_base, "WaitOnAddress");
  70                 if (BOOST_LIKELY(woa != NULL))
  71                 {
  72                     wake_by_address_t* wbas = (wake_by_address_t*)boost::winapi::get_proc_address(kernel_base, "WakeByAddressSingle");
  73                     wake_by_address_t* wbaa = (wake_by_address_t*)boost::winapi::get_proc_address(kernel_base, "WakeByAddressAll");
  74
  75                     if (BOOST_LIKELY(wbas != NULL && wbaa != NULL))
  76                     {
  77                         wait_on_address = woa;
  78                         wake_by_address_single = wbas;
  79                         wake_by_address_all = wbaa;
  80                     }
  81                 }
  82             }
  83
  84             once_flag_operations::store(wait_functions_once_flag.m_flag, 0u, boost::memory_order_release);
  85             break;
  86         }
  87         else if (old_val == 1u)
  88         {
  89             boost::winapi::SwitchToThread();
  90             old_val = once_flag_operations::load(wait_functions_once_flag.m_flag, boost::memory_order_acquire);
  91         }
  92         else
  93         {
  94             break;
  95         }
  96     }
  97 }
  98
  99 #else // BOOST_WINAPI_PARTITION_DESKTOP || BOOST_WINAPI_PARTITION_SYSTEM
 100
 101 BOOST_ATOMIC_DECL once_flag wait_functions_once_flag = { 0u };
 102
 103 BOOST_ATOMIC_DECL void initialize_wait_functions() BOOST_NOEXCEPT
 104 {
 105 }
 106
 107 #endif // BOOST_WINAPI_PARTITION_DESKTOP || BOOST_WINAPI_PARTITION_SYSTEM
 108
 109 } // namespace detail
 110 } // namespace atomics
 111 } // namespace boost
 112
 113 #include <boost/atomic/detail/footer.hpp>