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Commit a453e068 authored by Krishna Kumar's avatar Krishna Kumar Committed by David S. Miller
Browse files

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: default avatarKrishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 03a9a447

net/sched/sch_generic.c

+4 −4
Original line number Original line 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)

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];

		int band = prio2band[skb->priority & TC_PRIO_MAX];

		struct pfifo_fast_priv *priv = qdisc_priv(qdisc);

		struct pfifo_fast_priv *priv = qdisc_priv(qdisc);

		struct sk_buff_head *list = band2list(priv, band);

		struct sk_buff_head *list = band2list(priv, band);





	if (skb_queue_len(list) < qdisc_dev(qdisc)->tx_queue_len) {

		priv->bitmap |= (1 << band);

		priv->bitmap |= (1 << band);

		qdisc->q.qlen++;

		qdisc->q.qlen++;

		return __qdisc_enqueue_tail(skb, qdisc, list);

		return __qdisc_enqueue_tail(skb, qdisc, list);