numactl -hardware源码分析

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https://github.com/jmesmon/numactl/blob/0df3f720e606a3706700e0487ba19d720f50c4b8/numactl.c
可以看到numactl总共支持的命令如下：struct option opts[] = {
   {"interleave", 1, 0, 'i' },
   {"preferred", 1, 0, 'p' },
   {"cpubind", 1, 0, 'c' },
   {"cpunodebind", 1, 0, 'N' },
   {"physcpubind", 1, 0, 'C' },
   {"membind", 1, 0, 'm'},
   {"show", 0, 0, 's' },
   {"localalloc", 0,0, 'l'},
   {"hardware", 0,0,'H' },

   {"shm", 1, 0, 'S'},
   {"file", 1, 0, 'f'},
   {"offset", 1, 0, 'o'},
   {"length", 1, 0, 'L'},
   {"strict", 0, 0, 't'},
   {"shmmode", 1, 0, 'M'},
   {"dump", 0, 0, 'd'},
   {"dump-nodes", 0, 0, 'D'},
   {"shmid", 1, 0, 'I'},
   {"huge", 0, 0, 'u'},
   {"touch", 0, 0, 'T'},
   {"verify", 0, 0, 'V'}, /* undocumented - for debugging */
   { 0 }
};
我们重点看先hardware命令的实现，如下所示
void hardware(void)
{
   int i;
   int numnodes=0;
   int prevnode=-1;
   int skip=0;
   int maxnode = numa_max_node();

       for (i = 0; i <= maxnode; i++) {
       char buf[64];
       long long fr;
       unsigned long long sz = numa_node_size64(i, &fr);
       if (!numa_bitmask_isbitset(numa_nodes_ptr, i))
           continue;

       printf("node %d cpus:", i);
       print_node_cpus(i);
       printf("node %d size: %s\n", i, fmt_mem(sz, buf));
       printf("node %d free: %s\n", i, fmt_mem(fr, buf));
   }
   print_distances(maxnode);
}
原来是通过fr得到free的size，而fr是从numa_node_size64(i, &fr)得到的值
long long numa_node_size64(int node, long long *freep)
{
   size_t len = 0;
   char *line = NULL;
   long long size = -1;
   FILE *f;
   char fn[64];
   int ok = 0;
   int required = freep ? 2 : 1;

   if (freep)
       *freep = -1;
sprintf(fn,"/sys/devices/system/node/node%d/meminfo", node);
}
原来numa_node_size64也是从kernel 里面parse meminfo的值

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