fs/proc/loadavg.c

   1 #include <linux/fs.h>
   2 #include <linux/init.h>
   3 #include <linux/pid_namespace.h>
   4 #include <linux/proc_fs.h>
   5 #include <linux/sched.h>
   6 #include <linux/seq_file.h>
   7 #include <linux/seqlock.h>
   8 #include <linux/time.h>
   9
  10 #define LOAD_INT(x) ((x) >> FSHIFT)
  11 #define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
  12
  13 static int loadavg_proc_show(struct seq_file *m, void *v)
  14 {
  15         int a, b, c;
  16         unsigned long seq;
  17
  18         do {
  19                 seq = read_seqbegin(&xtime_lock);
  20                 a = avenrun[0] + (FIXED_1/200);
  21                 b = avenrun[1] + (FIXED_1/200);
  22                 c = avenrun[2] + (FIXED_1/200);
  23         } while (read_seqretry(&xtime_lock, seq));
  24
  25         seq_printf(m, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
  26                 LOAD_INT(a), LOAD_FRAC(a),
  27                 LOAD_INT(b), LOAD_FRAC(b),
  28                 LOAD_INT(c), LOAD_FRAC(c),
  29                 nr_running(), nr_threads,
  30                 task_active_pid_ns(current)->last_pid);
  31         return 0;
  32 }
  33
  34 static int loadavg_proc_open(struct inode *inode, struct file *file)
  35 {
  36         return single_open(file, loadavg_proc_show, NULL);
  37 }
  38
  39 static const struct file_operations loadavg_proc_fops = {
  40         .open           = loadavg_proc_open,
  41         .read           = seq_read,
  42         .llseek         = seq_lseek,
  43         .release        = single_release,
  44 };
  45
  46 static int __init proc_loadavg_init(void)
  47 {
  48         proc_create("loadavg", 0, NULL, &loadavg_proc_fops);
  49         return 0;
  50 }
  51 module_init(proc_loadavg_init);