procps/library/numa.c

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/*
* NUMA node support for <PIDS> & <STAT> interfaces
*
* Copyright © 2017-2023 Jim Warner <james.warner@comcast.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef NUMA_DISABLE
#include <dlfcn.h>
#endif
#include <stdlib.h>
#include "numa.h"
/*
* We're structured so that if numa_init() is NOT called or that ./configure |
* --disable-numa WAS specified, then calls to both of our primary functions |
* of numa_max_node() plus numa_node_of_cpu() would always return a negative |
* 1 which signifies that NUMA information isn't available. That ./configure |
* option might be required when libdl.so (necessary for dlopen) is missing. |
*/
/* ------------------------------------------------------------------------- +
a strictly development #define, existing specifically for the top program |
( and it has no affect if ./configure --disable-numa has been specified ) | */
//#define PRETEND_NUMA // pretend there are 3 'discontiguous' numa nodes |
// ------------------------------------------------------------------------- +
static int null_max_node (void) { return -1; }
static int null_node_of_cpu (int n) { (void)n; return -1; }
#ifndef NUMA_DISABLE
#ifdef PRETEND_NUMA
static int fake_max_node (void) { return 3; }
static int fake_node_of_cpu (int n) { return (1 == (n % 4)) ? 0 : (n % 4); }
#endif
#endif
#ifndef NUMA_DISABLE
static void *libnuma_handle;
#endif
int (*numa_max_node) (void) = null_max_node;
int (*numa_node_of_cpu) (int) = null_node_of_cpu;
void numa_init (void) {
static int initialized;
if (initialized)
return;
#ifndef NUMA_DISABLE
#ifndef PRETEND_NUMA
// we'll try for the most recent version, then a version we know works...
if ((libnuma_handle = dlopen("libnuma.so", RTLD_LAZY))
|| (libnuma_handle = dlopen("libnuma.so.1", RTLD_LAZY))) {
numa_max_node = dlsym(libnuma_handle, "numa_max_node");
numa_node_of_cpu = dlsym(libnuma_handle, "numa_node_of_cpu");
if (numa_max_node == NULL
|| (numa_node_of_cpu == NULL)) {
// this dlclose is safe - we've yet to call numa_node_of_cpu
// ( there's one other dlclose which has now been disabled )
dlclose(libnuma_handle);
libnuma_handle = NULL;
numa_max_node = null_max_node;
numa_node_of_cpu = null_node_of_cpu;
}
}
#else
libnuma_handle = (void *)-1;
numa_max_node = fake_max_node;
numa_node_of_cpu = fake_node_of_cpu;
#endif
#endif
initialized = 1;
} // end: numa_init
void numa_uninit (void) {
#ifndef PRETEND_NUMA
/* note: we'll skip a dlcose() to avoid the following libnuma memory
* leak which is triggered after a call to numa_node_of_cpu():
* ==1234== LEAK SUMMARY:
* ==1234== definitely lost: 512 bytes in 1 blocks
* ==1234== indirectly lost: 48 bytes in 2 blocks
* ==1234== ...
* [ thanks very much libnuma for all the pains you have caused us ]
*/
// if (libnuma_handle)
// dlclose(libnuma_handle);
#endif
} // end: numa_uninit
#if defined(PRETEND_NUMA) && defined(NUMA_DISABLE)
# warning 'PRETEND_NUMA' ignored, 'NUMA_DISABLE' is active
#endif