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/* $Id: RTMpGetArraySize-generic.cpp $ */
/** @file
* IPRT - Multiprocessor, Generic RTMpGetArraySize.
*/
/*
* Copyright (C) 2010-2019 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include <iprt/mp.h>
#include "internal/iprt.h"
#include <iprt/asm.h>
#include <iprt/cpuset.h>
RTDECL(uint32_t) RTMpGetArraySize(void)
{
/*
* Cache the result here. This whole point of this function is that it
* will always return the same value, so that should be safe.
*
* Note! Because RTCPUSET may be to small to represent all the CPUs, we
* check with RTMpGetCount() as well.
*/
static uint32_t s_cMaxCpus = 0;
uint32_t cCpus = s_cMaxCpus;
if (RT_UNLIKELY(cCpus == 0))
{
RTCPUSET CpuSet;
uint32_t cCpus1 = RTCpuLastIndex(RTMpGetSet(&CpuSet)) + 1;
uint32_t cCpus2 = RTMpGetCount();
cCpus = RT_MAX(cCpus1, cCpus2);
ASMAtomicCmpXchgU32(&s_cMaxCpus, cCpus, 0);
return cCpus;
}
return s_cMaxCpus;
}
RT_EXPORT_SYMBOL(RTMpGetArraySize);
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