xref: /linux/fs/proc/loadavg.c (revision 367b8112fe2ea5c39a7bb4d263dcdd9b612fae18)
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);
52