linux/fs/proc/uptime.c
Alexey Dobriyan ef1d61781b proc: mark more files as permanent
Mark
	/proc/devices
	/proc/kpagecount
	/proc/kpageflags
	/proc/kpagecgroup
	/proc/loadavg
	/proc/meminfo
	/proc/softirqs
	/proc/uptime
	/proc/version

as permanent /proc entries, saving alloc/free and some list/spinlock ops
per use.

These files are never removed by the kernel so it is OK to mark them.

Link: https://lkml.kernel.org/r/Yyn527DzDMa+r0Yj@localhost.localdomain
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-03 14:21:45 -07:00

50 lines
1.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/time.h>
#include <linux/time_namespace.h>
#include <linux/kernel_stat.h>
#include "internal.h"
static int uptime_proc_show(struct seq_file *m, void *v)
{
struct timespec64 uptime;
struct timespec64 idle;
u64 idle_nsec;
u32 rem;
int i;
idle_nsec = 0;
for_each_possible_cpu(i) {
struct kernel_cpustat kcs;
kcpustat_cpu_fetch(&kcs, i);
idle_nsec += get_idle_time(&kcs, i);
}
ktime_get_boottime_ts64(&uptime);
timens_add_boottime(&uptime);
idle.tv_sec = div_u64_rem(idle_nsec, NSEC_PER_SEC, &rem);
idle.tv_nsec = rem;
seq_printf(m, "%lu.%02lu %lu.%02lu\n",
(unsigned long) uptime.tv_sec,
(uptime.tv_nsec / (NSEC_PER_SEC / 100)),
(unsigned long) idle.tv_sec,
(idle.tv_nsec / (NSEC_PER_SEC / 100)));
return 0;
}
static int __init proc_uptime_init(void)
{
struct proc_dir_entry *pde;
pde = proc_create_single("uptime", 0, NULL, uptime_proc_show);
pde_make_permanent(pde);
return 0;
}
fs_initcall(proc_uptime_init);