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