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/* net/activity_stats.c
*
* Copyright (C) 2010 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Author: Mike Chan (mike@android.com)
*/
#include <linux/proc_fs.h>
#include <linux/suspend.h>
#include <net/net_namespace.h>
/*
* Track transmission rates in buckets (power of 2).
* 1,2,4,8...512 seconds.
*
* Buckets represent the count of network transmissions at least
* N seconds apart, where N is 1 << bucket index.
*/
#define BUCKET_MAX 10
/* Track network activity frequency */
static unsigned long activity_stats[BUCKET_MAX];
static ktime_t last_transmit;
static ktime_t suspend_time;
static DEFINE_SPINLOCK(activity_lock);
void activity_stats_update(void)
{
int i;
unsigned long flags;
ktime_t now;
s64 delta;
spin_lock_irqsave(&activity_lock, flags);
now = ktime_get();
delta = ktime_to_ns(ktime_sub(now, last_transmit));
for (i = BUCKET_MAX - 1; i >= 0; i--) {
/*
* Check if the time delta between network activity is within the
* minimum bucket range.
*/
if (delta < (1000000000ULL << i))
continue;
activity_stats[i]++;
last_transmit = now;
break;
}
spin_unlock_irqrestore(&activity_lock, flags);
}
static int activity_stats_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int i;
int len;
char *p = page;
/* Only print if offset is 0, or we have enough buffer space */
if (off || count < (30 * BUCKET_MAX + 22))
return -ENOMEM;
len = snprintf(p, count, "Min Bucket(sec) Count\n");
count -= len;
p += len;
for (i = 0; i < BUCKET_MAX; i++) {
len = snprintf(p, count, "%15d %lu\n", 1 << i, activity_stats[i]);
count -= len;
p += len;
}
*eof = 1;
return p - page;
}
static int activity_stats_notifier(struct notifier_block *nb,
unsigned long event, void *dummy)
{
switch (event) {
case PM_SUSPEND_PREPARE:
suspend_time = ktime_get_real();
break;
case PM_POST_SUSPEND:
suspend_time = ktime_sub(ktime_get_real(), suspend_time);
last_transmit = ktime_sub(last_transmit, suspend_time);
}
return 0;
}
static struct notifier_block activity_stats_notifier_block = {
.notifier_call = activity_stats_notifier,
};
static int __init activity_stats_init(void)
{
create_proc_read_entry("activity", S_IRUGO,
init_net.proc_net_stat, activity_stats_read_proc, NULL);
return register_pm_notifier(&activity_stats_notifier_block);
}
subsys_initcall(activity_stats_init);