Commit a453e068 authored Aug 30, 2009 by Krishna Kumar Committed by David S. Miller Aug 30, 2009

pkt_sched: Fix resource limiting in pfifo_fast



pfifo_fast_enqueue has this check:
        if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) {

which allows each band to enqueue upto tx_queue_len skbs for a
total of 3*tx_queue_len skbs. I am not sure if this was the
intention of limiting in qdisc.

Patch compiled and 32 simultaneous netperf testing ran fine. Also:
# tc -s qdisc show dev eth2
qdisc pfifo_fast 0: root bands 3 priomap  1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1
 Sent 16835026752 bytes 373116 pkt (dropped 0, overlimits 0 requeues 25) 
 rate 0bit 0pps backlog 0b 0p requeues 25 

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 03a9a447

net/sched/sch_generic.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -432,11 +432,11 @@ static inline struct sk_buff_head band2list(struct pfifo_fast_priv priv,

		static int pfifo_fast_enqueue(struct sk_buff skb, struct Qdisc qdisc)
		{
		if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) {
		int band = prio2band[skb->priority & TC_PRIO_MAX];
		struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
		struct sk_buff_head *list = band2list(priv, band);

		if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) {
		priv->bitmap \|= (1 << band);
		qdisc->q.qlen++;
		return __qdisc_enqueue_tail(skb, qdisc, list);

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