LXR linux/fs/proc/uptime.c

   1#include <linux/fs.h>
   2#include <linux/init.h>
   3#include <linux/proc_fs.h>
   4#include <linux/sched.h>
   5#include <linux/seq_file.h>
   6#include <linux/time.h>
   7#include <linux/kernel_stat.h>
   8#include <linux/cputime.h>
   9
  10static int uptime_proc_show(struct seq_file *m, void *v)
  11{
  12        struct timespec uptime;
  13        struct timespec idle;
  14        u64 idletime;
  15        u64 nsec;
  16        u32 rem;
  17        int i;
  18
  19        idletime = 0;
  20        for_each_possible_cpu(i)
  21                idletime += (__force u64) kcpustat_cpu(i).cpustat[CPUTIME_IDLE];
  22
  23        get_monotonic_boottime(&uptime);
  24        nsec = cputime64_to_jiffies64(idletime) * TICK_NSEC;
  25        idle.tv_sec = div_u64_rem(nsec, NSEC_PER_SEC, &rem);
  26        idle.tv_nsec = rem;
  27        seq_printf(m, "%lu.%02lu %lu.%02lu\n",
  28                        (unsigned long) uptime.tv_sec,
  29                        (uptime.tv_nsec / (NSEC_PER_SEC / 100)),
  30                        (unsigned long) idle.tv_sec,
  31                        (idle.tv_nsec / (NSEC_PER_SEC / 100)));
  32        return 0;
  33}
  34
  35static int uptime_proc_open(struct inode *inode, struct file *file)
  36{
  37        return single_open(file, uptime_proc_show, NULL);
  38}
  39
  40static const struct file_operations uptime_proc_fops = {
  41        .open           = uptime_proc_open,
  42        .read           = seq_read,
  43        .llseek         = seq_lseek,
  44        .release        = single_release,
  45};
  46
  47static int __init proc_uptime_init(void)
  48{
  49        proc_create("uptime", 0, NULL, &uptime_proc_fops);
  50        return 0;
  51}
  52fs_initcall(proc_uptime_init);
  53