| 1 | /* $Id: RTMpGetArraySize-generic.cpp 69111 2017-10-17 14:26:02Z vboxsync $ */
|
|---|
| 2 | /** @file
|
|---|
| 3 | * IPRT - Multiprocessor, Generic RTMpGetArraySize.
|
|---|
| 4 | */
|
|---|
| 5 |
|
|---|
| 6 | /*
|
|---|
| 7 | * Copyright (C) 2010-2017 Oracle Corporation
|
|---|
| 8 | *
|
|---|
| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
|
|---|
| 10 | * available from http://www.virtualbox.org. This file is free software;
|
|---|
| 11 | * you can redistribute it and/or modify it under the terms of the GNU
|
|---|
| 12 | * General Public License (GPL) as published by the Free Software
|
|---|
| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
|
|---|
| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
|
|---|
| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
|
|---|
| 16 | *
|
|---|
| 17 | * The contents of this file may alternatively be used under the terms
|
|---|
| 18 | * of the Common Development and Distribution License Version 1.0
|
|---|
| 19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
|
|---|
| 20 | * VirtualBox OSE distribution, in which case the provisions of the
|
|---|
| 21 | * CDDL are applicable instead of those of the GPL.
|
|---|
| 22 | *
|
|---|
| 23 | * You may elect to license modified versions of this file under the
|
|---|
| 24 | * terms and conditions of either the GPL or the CDDL or both.
|
|---|
| 25 | */
|
|---|
| 26 |
|
|---|
| 27 |
|
|---|
| 28 | /*********************************************************************************************************************************
|
|---|
| 29 | * Header Files *
|
|---|
| 30 | *********************************************************************************************************************************/
|
|---|
| 31 | #include <iprt/mp.h>
|
|---|
| 32 | #include "internal/iprt.h"
|
|---|
| 33 |
|
|---|
| 34 | #include <iprt/asm.h>
|
|---|
| 35 | #include <iprt/cpuset.h>
|
|---|
| 36 |
|
|---|
| 37 |
|
|---|
| 38 | RTDECL(uint32_t) RTMpGetArraySize(void)
|
|---|
| 39 | {
|
|---|
| 40 | /*
|
|---|
| 41 | * Cache the result here. This whole point of this function is that it
|
|---|
| 42 | * will always return the same value, so that should be safe.
|
|---|
| 43 | *
|
|---|
| 44 | * Note! Because RTCPUSET may be to small to represent all the CPUs, we
|
|---|
| 45 | * check with RTMpGetCount() as well.
|
|---|
| 46 | */
|
|---|
| 47 | static uint32_t s_cMaxCpus = 0;
|
|---|
| 48 | uint32_t cCpus = s_cMaxCpus;
|
|---|
| 49 | if (RT_UNLIKELY(cCpus == 0))
|
|---|
| 50 | {
|
|---|
| 51 | RTCPUSET CpuSet;
|
|---|
| 52 | uint32_t cCpus1 = RTCpuLastIndex(RTMpGetSet(&CpuSet)) + 1;
|
|---|
| 53 | uint32_t cCpus2 = RTMpGetCount();
|
|---|
| 54 | cCpus = RT_MAX(cCpus1, cCpus2);
|
|---|
| 55 | ASMAtomicCmpXchgU32(&s_cMaxCpus, cCpus, 0);
|
|---|
| 56 | return cCpus;
|
|---|
| 57 | }
|
|---|
| 58 | return s_cMaxCpus;
|
|---|
| 59 |
|
|---|
| 60 | }
|
|---|
| 61 | RT_EXPORT_SYMBOL(RTMpGetArraySize);
|
|---|
| 62 |
|
|---|
