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mirror of https://gitlab.isc.org/isc-projects/bind9 synced 2025-08-24 11:08:45 +00:00
bind/lib/isc/os.c
Ondřej Surý b28327354d Ignore the invalid L1 cache line size returned by sysconf()
On some systems, the glibc can return 0 instead of cache-line size to
indicate the cache line sizes cannot be determined.  This is comment
from glibc source code:

    /* In general we cannot determine these values.  Therefore we
       return zero which indicates that no information is
       available.  */

As the goal of the check is to determine whether the L1 cache line size
is still 64 and we would use this value in case the sysconf() call is
not available, we can also ignore the invalid values returned by the
sysconf() call.
2022-01-22 16:59:50 +01:00

92 lines
2.1 KiB
C

/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* SPDX-License-Identifier: MPL-2.0
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, you can obtain one at https://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
#include <inttypes.h>
#include <isc/os.h>
#include <isc/types.h>
#include <isc/util.h>
#include "os_p.h"
static unsigned int isc__os_ncpus = 0;
#ifdef HAVE_SYSCONF
#include <unistd.h>
static inline long
sysconf_ncpus(void) {
#if defined(_SC_NPROCESSORS_ONLN)
return (sysconf((_SC_NPROCESSORS_ONLN)));
#elif defined(_SC_NPROC_ONLN)
return (sysconf((_SC_NPROC_ONLN)));
#else /* if defined(_SC_NPROCESSORS_ONLN) */
return (0);
#endif /* if defined(_SC_NPROCESSORS_ONLN) */
}
#endif /* HAVE_SYSCONF */
#if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME)
#include <sys/param.h> /* for NetBSD */
#include <sys/sysctl.h>
#include <sys/types.h> /* for FreeBSD */
static int
sysctl_ncpus(void) {
int ncpu, result;
size_t len;
len = sizeof(ncpu);
result = sysctlbyname("hw.ncpu", &ncpu, &len, 0, 0);
if (result != -1) {
return (ncpu);
}
return (0);
}
#endif /* if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) */
static void
ncpus_initialize(void) {
#if defined(HAVE_SYSCONF)
isc__os_ncpus = sysconf_ncpus();
#endif /* if defined(HAVE_SYSCONF) */
#if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME)
if (isc__os_ncpus <= 0) {
isc__os_ncpus = sysctl_ncpus();
}
#endif /* if defined(HAVE_SYS_SYSCTL_H) && defined(HAVE_SYSCTLBYNAME) */
if (isc__os_ncpus == 0) {
isc__os_ncpus = 1;
}
}
unsigned int
isc_os_ncpus(void) {
return (isc__os_ncpus);
}
void
isc__os_initialize(void) {
ncpus_initialize();
#if defined(HAVE_SYSCONF) && defined(_SC_LEVEL1_DCACHE_LINESIZE)
long s = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
RUNTIME_CHECK((size_t)s == (size_t)ISC_OS_CACHELINE_SIZE || s <= 0);
#endif
}
void
isc__os_shutdown(void) {
/* empty, but defined for completeness */;
}