proc: move /proc/stat to fs/proc/stat.c

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
diff --git a/fs/proc/stat.c b/fs/proc/stat.c
new file mode 100644
index 0000000..81904f0
--- /dev/null
+++ b/fs/proc/stat.c
@@ -0,0 +1,153 @@
+#include <linux/cpumask.h>
+#include <linux/fs.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+#include <linux/proc_fs.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <asm/cputime.h>
+
+#ifndef arch_irq_stat_cpu
+#define arch_irq_stat_cpu(cpu) 0
+#endif
+#ifndef arch_irq_stat
+#define arch_irq_stat() 0
+#endif
+
+static int show_stat(struct seq_file *p, void *v)
+{
+	int i, j;
+	unsigned long jif;
+	cputime64_t user, nice, system, idle, iowait, irq, softirq, steal;
+	cputime64_t guest;
+	u64 sum = 0;
+	struct timespec boottime;
+	unsigned int per_irq_sum;
+
+	user = nice = system = idle = iowait =
+		irq = softirq = steal = cputime64_zero;
+	guest = cputime64_zero;
+	getboottime(&boottime);
+	jif = boottime.tv_sec;
+
+	for_each_possible_cpu(i) {
+		user = cputime64_add(user, kstat_cpu(i).cpustat.user);
+		nice = cputime64_add(nice, kstat_cpu(i).cpustat.nice);
+		system = cputime64_add(system, kstat_cpu(i).cpustat.system);
+		idle = cputime64_add(idle, kstat_cpu(i).cpustat.idle);
+		iowait = cputime64_add(iowait, kstat_cpu(i).cpustat.iowait);
+		irq = cputime64_add(irq, kstat_cpu(i).cpustat.irq);
+		softirq = cputime64_add(softirq, kstat_cpu(i).cpustat.softirq);
+		steal = cputime64_add(steal, kstat_cpu(i).cpustat.steal);
+		guest = cputime64_add(guest, kstat_cpu(i).cpustat.guest);
+
+		for_each_irq_nr(j)
+			sum += kstat_irqs_cpu(j, i);
+
+		sum += arch_irq_stat_cpu(i);
+	}
+	sum += arch_irq_stat();
+
+	seq_printf(p, "cpu  %llu %llu %llu %llu %llu %llu %llu %llu %llu\n",
+		(unsigned long long)cputime64_to_clock_t(user),
+		(unsigned long long)cputime64_to_clock_t(nice),
+		(unsigned long long)cputime64_to_clock_t(system),
+		(unsigned long long)cputime64_to_clock_t(idle),
+		(unsigned long long)cputime64_to_clock_t(iowait),
+		(unsigned long long)cputime64_to_clock_t(irq),
+		(unsigned long long)cputime64_to_clock_t(softirq),
+		(unsigned long long)cputime64_to_clock_t(steal),
+		(unsigned long long)cputime64_to_clock_t(guest));
+	for_each_online_cpu(i) {
+
+		/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
+		user = kstat_cpu(i).cpustat.user;
+		nice = kstat_cpu(i).cpustat.nice;
+		system = kstat_cpu(i).cpustat.system;
+		idle = kstat_cpu(i).cpustat.idle;
+		iowait = kstat_cpu(i).cpustat.iowait;
+		irq = kstat_cpu(i).cpustat.irq;
+		softirq = kstat_cpu(i).cpustat.softirq;
+		steal = kstat_cpu(i).cpustat.steal;
+		guest = kstat_cpu(i).cpustat.guest;
+		seq_printf(p,
+			"cpu%d %llu %llu %llu %llu %llu %llu %llu %llu %llu\n",
+			i,
+			(unsigned long long)cputime64_to_clock_t(user),
+			(unsigned long long)cputime64_to_clock_t(nice),
+			(unsigned long long)cputime64_to_clock_t(system),
+			(unsigned long long)cputime64_to_clock_t(idle),
+			(unsigned long long)cputime64_to_clock_t(iowait),
+			(unsigned long long)cputime64_to_clock_t(irq),
+			(unsigned long long)cputime64_to_clock_t(softirq),
+			(unsigned long long)cputime64_to_clock_t(steal),
+			(unsigned long long)cputime64_to_clock_t(guest));
+	}
+	seq_printf(p, "intr %llu", (unsigned long long)sum);
+
+	/* sum again ? it could be updated? */
+	for_each_irq_nr(j) {
+		per_irq_sum = 0;
+
+		for_each_possible_cpu(i)
+			per_irq_sum += kstat_irqs_cpu(j, i);
+
+		seq_printf(p, " %u", per_irq_sum);
+	}
+
+	seq_printf(p,
+		"\nctxt %llu\n"
+		"btime %lu\n"
+		"processes %lu\n"
+		"procs_running %lu\n"
+		"procs_blocked %lu\n",
+		nr_context_switches(),
+		(unsigned long)jif,
+		total_forks,
+		nr_running(),
+		nr_iowait());
+
+	return 0;
+}
+
+static int stat_open(struct inode *inode, struct file *file)
+{
+	unsigned size = 4096 * (1 + num_possible_cpus() / 32);
+	char *buf;
+	struct seq_file *m;
+	int res;
+
+	/* don't ask for more than the kmalloc() max size, currently 128 KB */
+	if (size > 128 * 1024)
+		size = 128 * 1024;
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	res = single_open(file, show_stat, NULL);
+	if (!res) {
+		m = file->private_data;
+		m->buf = buf;
+		m->size = size;
+	} else
+		kfree(buf);
+	return res;
+}
+
+static const struct file_operations proc_stat_operations = {
+	.open		= stat_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init proc_stat_init(void)
+{
+	proc_create("stat", 0, NULL, &proc_stat_operations);
+	return 0;
+}
+module_init(proc_stat_init);