netdev - Re: [patch net-next v5 10/11] tbf: take into account gso skbs

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Date:	Tue, 12 Feb 2013 08:39:42 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Jiri Pirko <jiri@...nulli.us>
Cc:	netdev@...r.kernel.org, davem@...emloft.net, edumazet@...gle.com,
	jhs@...atatu.com, kuznet@....inr.ac.ru, j.vimal@...il.com
Subject: Re: [patch net-next v5 10/11] tbf: take into account gso skbs

On Tue, 2013-02-12 at 11:12 +0100, Jiri Pirko wrote:
> Ignore max_size check for gso skbs. This check made bigger packets
> incorrectly dropped. Remove this limitation for gso skbs.
> 
> Also for peaks, ignore mtu for gso skbs.
> 
> Signed-off-by: Jiri Pirko <jiri@...nulli.us>
> ---
>  net/sched/sch_tbf.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c
> index c8388f3..8973e93 100644
> --- a/net/sched/sch_tbf.c
> +++ b/net/sched/sch_tbf.c
> @@ -121,7 +121,7 @@ static int tbf_enqueue(struct sk_buff *skb, struct Qdisc *sch)
>  	struct tbf_sched_data *q = qdisc_priv(sch);
>  	int ret;
>  
> -	if (qdisc_pkt_len(skb) > q->max_size)
> +	if (qdisc_pkt_len(skb) > q->max_size && !skb_is_gso(skb))
>  		return qdisc_reshape_fail(skb, sch);
>  
>  	ret = qdisc_enqueue(skb, q->qdisc);
> @@ -165,7 +165,7 @@ static struct sk_buff *tbf_dequeue(struct Qdisc *sch)
>  
>  		if (q->peak_present) {
>  			ptoks = toks + q->ptokens;
> -			if (ptoks > q->mtu)
> +			if (ptoks > q->mtu && !skb_is_gso(skb))
>  				ptoks = q->mtu;
>  			ptoks -= (s64) psched_l2t_ns(&q->peak, len);
>  		}


I guess this part is wrong.

If we dont cap ptoks to q->mtu we allow bigger bursts.

Ideally we could re-segment the skb if psched_l2t_ns(&q->peak, len) is
bigger than q->mtu






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