allocators.cpp

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// Copyright (c) 2009-2013 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#include "allocators.h"
 
#ifdef WIN32
#ifndef NOMINMAX
#define NOMINMAX
#endif
#include <windows.h>
// This is used to attempt to keep keying material out of swap
// Note that VirtualLock does not provide this as a guarantee on Windows,
// but, in practice, memory that has been VirtualLock'd almost never gets written to
// the pagefile except in rare circumstances where memory is extremely low.
#else
#include <limits.h> // for PAGESIZE
#include <sys/mman.h>
#include <unistd.h> // for sysconf
#endif
 
LockedPageManager* LockedPageManager::_instance = NULL;
boost::once_flag LockedPageManager::init_flag = BOOST_ONCE_INIT;
 
static inline size_t GetSystemPageSize()
{
    size_t page_size;
#if defined(WIN32)
    SYSTEM_INFO sSysInfo;
    GetSystemInfo(&sSysInfo);
    page_size = sSysInfo.dwPageSize;
#elif defined(PAGESIZE) // defined in limits.h
    page_size = PAGESIZE;
#else                   // assume some POSIX OS
    page_size = sysconf(_SC_PAGESIZE);
#endif
    return page_size;
}
 
bool MemoryPageLocker::Lock(const void* addr, size_t len)
{
#ifdef WIN32
    return VirtualLock(const_cast<void*>(addr), len) != 0;
#else
    return mlock(addr, len) == 0;
#endif
}
 
bool MemoryPageLocker::Unlock(const void* addr, size_t len)
{
#ifdef WIN32
    return VirtualUnlock(const_cast<void*>(addr), len) != 0;
#else
    return munlock(addr, len) == 0;
#endif
}
 
LockedPageManager::LockedPageManager() : LockedPageManagerBase<MemoryPageLocker>(GetSystemPageSize())
{
}