예제 #1
0
static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
	struct fq_codel_sched_data *q = qdisc_priv(sch);
	unsigned int idx;
	struct fq_codel_flow *flow;
	int uninitialized_var(ret);

	idx = fq_codel_classify(skb, sch, &ret);
	if (idx == 0) {
		if (ret & __NET_XMIT_BYPASS)
			qdisc_qstats_drop(sch);
		kfree_skb(skb);
		return ret;
	}
	idx--;
	if (sch->q.qlen > 128)
		skb = skb_reduce_truesize(skb);

	codel_set_enqueue_time(skb);
	flow = &q->flows[idx];
	flow_queue_add(flow, skb);
	q->backlogs[idx] += qdisc_pkt_len(skb);
	qdisc_qstats_backlog_inc(sch, skb);

	if (list_empty(&flow->flowchain)) {
		list_add_tail(&flow->flowchain, &q->new_flows);
		q->new_flow_count++;
		flow->deficit = q->quantum;
		flow->dropped = 0;
	}
	if (++sch->q.qlen <= sch->limit)
		return NET_XMIT_SUCCESS;

	q->drop_overlimit++;
	/* Return Congestion Notification only if we dropped a packet
	 * from this flow.
	 */
	if (fq_codel_drop(sch) == idx)
		return NET_XMIT_CN;

	/* As we dropped a packet, better let upper stack know this */
	qdisc_tree_decrease_qlen(sch, 1);
	return NET_XMIT_SUCCESS;
}
예제 #2
0
파일: sch_fq_codel.c 프로젝트: Lyude/linux
static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch,
			    struct sk_buff **to_free)
{
	struct fq_codel_sched_data *q = qdisc_priv(sch);
	unsigned int idx, prev_backlog, prev_qlen;
	struct fq_codel_flow *flow;
	int uninitialized_var(ret);
	unsigned int pkt_len;
	bool memory_limited;

	idx = fq_codel_classify(skb, sch, &ret);
	if (idx == 0) {
		if (ret & __NET_XMIT_BYPASS)
			qdisc_qstats_drop(sch);
		__qdisc_drop(skb, to_free);
		return ret;
	}
	idx--;

	codel_set_enqueue_time(skb);
	flow = &q->flows[idx];
	flow_queue_add(flow, skb);
	q->backlogs[idx] += qdisc_pkt_len(skb);
	qdisc_qstats_backlog_inc(sch, skb);

	if (list_empty(&flow->flowchain)) {
		list_add_tail(&flow->flowchain, &q->new_flows);
		q->new_flow_count++;
		flow->deficit = q->quantum;
		flow->dropped = 0;
	}
	get_codel_cb(skb)->mem_usage = skb->truesize;
	q->memory_usage += get_codel_cb(skb)->mem_usage;
	memory_limited = q->memory_usage > q->memory_limit;
	if (++sch->q.qlen <= sch->limit && !memory_limited)
		return NET_XMIT_SUCCESS;

	prev_backlog = sch->qstats.backlog;
	prev_qlen = sch->q.qlen;

	/* save this packet length as it might be dropped by fq_codel_drop() */
	pkt_len = qdisc_pkt_len(skb);
	/* fq_codel_drop() is quite expensive, as it performs a linear search
	 * in q->backlogs[] to find a fat flow.
	 * So instead of dropping a single packet, drop half of its backlog
	 * with a 64 packets limit to not add a too big cpu spike here.
	 */
	ret = fq_codel_drop(sch, q->drop_batch_size, to_free);

	prev_qlen -= sch->q.qlen;
	prev_backlog -= sch->qstats.backlog;
	q->drop_overlimit += prev_qlen;
	if (memory_limited)
		q->drop_overmemory += prev_qlen;

	/* As we dropped packet(s), better let upper stack know this.
	 * If we dropped a packet for this flow, return NET_XMIT_CN,
	 * but in this case, our parents wont increase their backlogs.
	 */
	if (ret == idx) {
		qdisc_tree_reduce_backlog(sch, prev_qlen - 1,
					  prev_backlog - pkt_len);
		return NET_XMIT_CN;
	}
	qdisc_tree_reduce_backlog(sch, prev_qlen, prev_backlog);
	return NET_XMIT_SUCCESS;
}