VirtualBox

source: vbox/trunk/src/VBox/Runtime/generic/RTMpGetArraySize-generic.cpp@ 61572

Last change on this file since 61572 was 57358, checked in by vboxsync, 9 years ago

*: scm cleanup run.

  • Property svn:eol-style set to native
  • Property svn:keywords set to Author Date Id Revision
File size: 2.3 KB
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1/* $Id: RTMpGetArraySize-generic.cpp 57358 2015-08-14 15:16:38Z vboxsync $ */
2/** @file
3 * IPRT - Multiprocessor, Generic RTMpGetArraySize.
4 */
5
6/*
7 * Copyright (C) 2010-2015 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
38RTDECL(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}
61RT_EXPORT_SYMBOL(RTMpGetArraySize);
62
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