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Commit f9ab7425 authored by Gao Feng's avatar Gao Feng Committed by David S. Miller
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sched: sfq: drop packets after root qdisc lock is released 



The commit 520ac30f ("net_sched: drop packets after root qdisc lock
is released) made a big change of tc for performance. But there are
some points which are not changed in SFQ enqueue operation.
1. Fail to find the SFQ hash slot;
2. When the queue is full;

Now use qdisc_drop instead free skb directly.

Signed-off-by: default avatarGao Feng <gfree.wind@vip.163.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f7423eea

net/sched/sch_sfq.c

+13 −7
Original line number Diff line number Diff line
@@ -292,7 +292,7 @@ static inline void slot_queue_add(struct sfq_slot *slot, struct sk_buff *skb) 
	slot->skblist_prev = skb;

}



static unsigned int sfq_drop(struct Qdisc *sch)

static unsigned int sfq_drop(struct Qdisc *sch, struct sk_buff **to_free)

{

	struct sfq_sched_data *q = qdisc_priv(sch);

	sfq_index x, d = q->cur_depth;
@@ -310,9 +310,8 @@ static unsigned int sfq_drop(struct Qdisc *sch) 
		slot->backlog -= len;

		sfq_dec(q, x);

		sch->q.qlen--;

		qdisc_qstats_drop(sch);

		qdisc_qstats_backlog_dec(sch, skb);

		kfree_skb(skb);

		qdisc_drop(skb, sch, to_free);

		return len;

	}
@@ -360,7 +359,7 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) 
	if (hash == 0) {

		if (ret & __NET_XMIT_BYPASS)

			qdisc_qstats_drop(sch);

		kfree_skb(skb);

		__qdisc_drop(skb, to_free);

		return ret;

	}

	hash--;
@@ -465,7 +464,7 @@ sfq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) 
		return NET_XMIT_SUCCESS;



	qlen = slot->qlen;

	dropped = sfq_drop(sch);

	dropped = sfq_drop(sch, to_free);

	/* Return Congestion Notification only if we dropped a packet

	 * from this flow.

	 */
@@ -628,6 +627,8 @@ static int sfq_change(struct Qdisc *sch, struct nlattr *opt) 
	struct tc_sfq_qopt_v1 *ctl_v1 = NULL;

	unsigned int qlen, dropped = 0;

	struct red_parms *p = NULL;

	struct sk_buff *to_free = NULL;

	struct sk_buff *tail = NULL;



	if (opt->nla_len < nla_attr_size(sizeof(*ctl)))

		return -EINVAL;
@@ -674,8 +675,13 @@ static int sfq_change(struct Qdisc *sch, struct nlattr *opt) 
	}



	qlen = sch->q.qlen;

	while (sch->q.qlen > q->limit)

		dropped += sfq_drop(sch);

	while (sch->q.qlen > q->limit) {

		dropped += sfq_drop(sch, &to_free);

		if (!tail)

			tail = to_free;

	}



	rtnl_kfree_skbs(to_free, tail);

	qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped);



	del_timer(&q->perturb_timer);