static void est_timer(unsigned long arg)
{
struct net_rate_estimator *est = (struct net_rate_estimator *)arg;
struct gnet_stats_basic_packed b;
u64 rate, brate;
est_fetch_counters(est, &b);
brate = (b.bytes - est->last_bytes) << (8 - est->ewma_log);
brate -= (est->avbps >> est->ewma_log);
rate = (u64)(b.packets - est->last_packets) << (8 - est->ewma_log);
rate -= (est->avpps >> est->ewma_log);
write_seqcount_begin(&est->seq);
est->avbps += brate;
est->avpps += rate;
write_seqcount_end(&est->seq);
est->last_bytes = b.bytes;
est->last_packets = b.packets;
est->next_jiffies += ((HZ/4) << est->intvl_log);
if (unlikely(time_after_eq(jiffies, est->next_jiffies))) {
/* Ouch... timer was delayed. */
est->next_jiffies = jiffies + 1;
}
mod_timer(&est->timer, est->next_jiffies);
}
/**
* gen_new_estimator - create a new rate estimator
* @bstats: basic statistics
* @cpu_bstats: bstats per cpu
* @rate_est: rate estimator statistics
* @stats_lock: statistics lock
* @running: qdisc running seqcount
* @opt: rate estimator configuration TLV
*
* Creates a new rate estimator with &bstats as source and &rate_est
* as destination. A new timer with the interval specified in the
* configuration TLV is created. Upon each interval, the latest statistics
* will be read from &bstats and the estimated rate will be stored in
* &rate_est with the statistics lock grabbed during this period.
*
* Returns 0 on success or a negative error code.
*
*/
int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
struct gnet_stats_basic_cpu __percpu *cpu_bstats,
struct net_rate_estimator __rcu **rate_est,
spinlock_t *stats_lock,
seqcount_t *running,
struct nlattr *opt)
{
struct gnet_estimator *parm = nla_data(opt);
struct net_rate_estimator *old, *est;
struct gnet_stats_basic_packed b;
int intvl_log;
if (nla_len(opt) < sizeof(*parm))
return -EINVAL;
/* allowed timer periods are :
* -2 : 250ms, -1 : 500ms, 0 : 1 sec
* 1 : 2 sec, 2 : 4 sec, 3 : 8 sec
*/
if (parm->interval < -2 || parm->interval > 3)
return -EINVAL;
est = kzalloc(sizeof(*est), GFP_KERNEL);
if (!est)
return -ENOBUFS;
seqcount_init(&est->seq);
intvl_log = parm->interval + 2;
est->bstats = bstats;
est->stats_lock = stats_lock;
est->running = running;
est->ewma_log = parm->ewma_log;
est->intvl_log = intvl_log;
est->cpu_bstats = cpu_bstats;
if (stats_lock)
local_bh_disable();
est_fetch_counters(est, &b);
if (stats_lock)
local_bh_enable();
est->last_bytes = b.bytes;
est->last_packets = b.packets;
old = rcu_dereference_protected(*rate_est, 1);
if (old) {
del_timer_sync(&old->timer);
est->avbps = old->avbps;
est->avpps = old->avpps;
}
est->next_jiffies = jiffies + ((HZ/4) << intvl_log);
timer_setup(&est->timer, est_timer, 0);
mod_timer(&est->timer, est->next_jiffies);
rcu_assign_pointer(*rate_est, est);
if (old)
kfree_rcu(old, rcu);
return 0;
}
