/usr/include/boost/atomic/detail
Edit: /usr/include/boost/atomic/detail/lock_pool.hpp (4689B)
/*
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* Copyright (c) 2011 Helge Bahmann
* Copyright (c) 2013-2014, 2020 Andrey Semashev
*/
/*!
* \file atomic/detail/lock_pool.hpp
*
* This header contains declaration of the lock pool used to emulate atomic ops.
*/
#ifndef BOOST_ATOMIC_DETAIL_LOCK_POOL_HPP_INCLUDED_
#define BOOST_ATOMIC_DETAIL_LOCK_POOL_HPP_INCLUDED_
#include
#include
#include
#include
#if defined(BOOST_WINDOWS)
#include
#elif defined(BOOST_HAS_NANOSLEEP)
#include
#else
#include
#endif
#include
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
namespace atomics {
namespace detail {
BOOST_FORCEINLINE void wait_some() BOOST_NOEXCEPT
{
#if defined(BOOST_WINDOWS)
boost::winapi::SwitchToThread();
#elif defined(BOOST_HAS_NANOSLEEP)
// Do not use sched_yield or pthread_yield as at least on Linux it doesn't block the thread if there are no other
// pending threads on the current CPU. Proper sleeping is guaranteed to block the thread, which allows other threads
// to potentially migrate to this CPU and complete the tasks we're waiting for.
struct ::timespec ts = {};
ts.tv_sec = 0;
ts.tv_nsec = 1000;
::nanosleep(&ts, NULL);
#else
::usleep(1);
#endif
}
namespace lock_pool {
BOOST_ATOMIC_DECL void* short_lock(atomics::detail::uintptr_t h) BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void* long_lock(atomics::detail::uintptr_t h) BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void unlock(void* ls) BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void* allocate_wait_state(void* ls, const volatile void* addr) BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void free_wait_state(void* ls, void* ws) BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void wait(void* ls, void* ws) BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void notify_one(void* ls, const volatile void* addr) BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void notify_all(void* ls, const volatile void* addr) BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void thread_fence() BOOST_NOEXCEPT;
BOOST_ATOMIC_DECL void signal_fence() BOOST_NOEXCEPT;
template< std::size_t Alignment >
BOOST_FORCEINLINE atomics::detail::uintptr_t hash_ptr(const volatile void* addr) BOOST_NOEXCEPT
{
atomics::detail::uintptr_t ptr = (atomics::detail::uintptr_t)addr;
atomics::detail::uintptr_t h = ptr / Alignment;
// Since many malloc/new implementations return pointers with higher alignment
// than indicated by Alignment, it makes sense to mix higher bits
// into the lower ones. On 64-bit platforms, malloc typically aligns to 16 bytes,
// on 32-bit - to 8 bytes.
BOOST_CONSTEXPR_OR_CONST std::size_t malloc_alignment = sizeof(void*) >= 8u ? 16u : 8u;
BOOST_IF_CONSTEXPR (Alignment != malloc_alignment)
h ^= ptr / malloc_alignment;
return h;
}
template< std::size_t Alignment, bool LongLock = false >
class scoped_lock
{
private:
void* m_lock;
public:
explicit scoped_lock(const volatile void* addr) BOOST_NOEXCEPT
{
atomics::detail::uintptr_t h = lock_pool::hash_ptr< Alignment >(addr);
BOOST_IF_CONSTEXPR (!LongLock)
m_lock = lock_pool::short_lock(h);
else
m_lock = lock_pool::long_lock(h);
}
~scoped_lock() BOOST_NOEXCEPT
{
lock_pool::unlock(m_lock);
}
void* get_lock_state() const BOOST_NOEXCEPT
{
return m_lock;
}
BOOST_DELETED_FUNCTION(scoped_lock(scoped_lock const&))
BOOST_DELETED_FUNCTION(scoped_lock& operator=(scoped_lock const&))
};
template< std::size_t Alignment >
class scoped_wait_state :
public scoped_lock< Alignment, true >
{
private:
void* m_wait_state;
public:
explicit scoped_wait_state(const volatile void* addr) BOOST_NOEXCEPT :
scoped_lock< Alignment, true >(addr)
{
m_wait_state = lock_pool::allocate_wait_state(this->get_lock_state(), addr);
}
~scoped_wait_state() BOOST_NOEXCEPT
{
lock_pool::free_wait_state(this->get_lock_state(), m_wait_state);
}
void wait() BOOST_NOEXCEPT
{
lock_pool::wait(this->get_lock_state(), m_wait_state);
}
BOOST_DELETED_FUNCTION(scoped_wait_state(scoped_wait_state const&))
BOOST_DELETED_FUNCTION(scoped_wait_state& operator=(scoped_wait_state const&))
};
} // namespace lock_pool
} // namespace detail
} // namespace atomics
} // namespace boost
#include
#endif // BOOST_ATOMIC_DETAIL_LOCK_POOL_HPP_INCLUDED_