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From: Jakub Kicinski <kuba@kernel.org>
To: Ido Schimmel <idosch@idosch.org>
Cc: netdev@vger.kernel.org, davem@davemloft.net, jiri@mellanox.com,
	petrm@mellanox.com, jhs@mojatatu.com, xiyou.wangcong@gmail.com,
	mlxsw@mellanox.com, Ido Schimmel <idosch@mellanox.com>
Subject: Re: [PATCH net-next 3/6] net: sched: RED: Introduce an ECN tail-dropping mode
Date: Mon, 9 Mar 2020 15:12:55 -0700	[thread overview]
Message-ID: <20200309151255.29bb3a4b@kicinski-fedora-PC1C0HJN> (raw)
In-Reply-To: <20200309183503.173802-4-idosch@idosch.org>

On Mon,  9 Mar 2020 20:35:00 +0200 Ido Schimmel wrote:
> diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
> index f9839d68b811..d72db7643a37 100644
> --- a/net/sched/sch_red.c
> +++ b/net/sched/sch_red.c
> @@ -44,7 +44,8 @@ struct red_sched_data {
>  	struct Qdisc		*qdisc;
>  };
>  
> -#define RED_SUPPORTED_FLAGS (TC_RED_ECN | TC_RED_HARDDROP | TC_RED_ADAPTATIVE)
> +#define RED_SUPPORTED_FLAGS (TC_RED_ECN | TC_RED_HARDDROP | \
> +			     TC_RED_ADAPTATIVE | TC_RED_TAILDROP)
>  
>  static inline int red_use_ecn(struct red_sched_data *q)
>  {
> @@ -56,6 +57,11 @@ static inline int red_use_harddrop(struct red_sched_data *q)
>  	return q->flags & TC_RED_HARDDROP;
>  }
>  
> +static inline int red_use_taildrop(struct red_sched_data *q)

Please don't do static inlines in C code, even if the neighboring code
does.

> +{
> +	return q->flags & TC_RED_TAILDROP;
> +}
> +
>  static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
>  		       struct sk_buff **to_free)
>  {
> @@ -76,23 +82,36 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch,
>  
>  	case RED_PROB_MARK:
>  		qdisc_qstats_overlimit(sch);
> -		if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) {
> +		if (!red_use_ecn(q)) {
>  			q->stats.prob_drop++;
>  			goto congestion_drop;
>  		}
>  
> -		q->stats.prob_mark++;
> +		if (INET_ECN_set_ce(skb)) {
> +			q->stats.prob_mark++;
> +		} else if (red_use_taildrop(q)) {

This condition is inverted, no?

If user requested taildrop the packet should be queued.

> +			q->stats.prob_drop++;
> +			goto congestion_drop;
> +		}
> +
> +		/* Non-ECT packet in ECN taildrop mode: queue it. */
>  		break;
>  
>  	case RED_HARD_MARK:
>  		qdisc_qstats_overlimit(sch);
> -		if (red_use_harddrop(q) || !red_use_ecn(q) ||
> -		    !INET_ECN_set_ce(skb)) {
> +		if (red_use_harddrop(q) || !red_use_ecn(q)) {
> +			q->stats.forced_drop++;
> +			goto congestion_drop;
> +		}
> +
> +		if (INET_ECN_set_ce(skb)) {
> +			q->stats.forced_mark++;
> +		} else if (!red_use_taildrop(q)) {

This one looks correct.

>  			q->stats.forced_drop++;
>  			goto congestion_drop;
>  		}
>  
> -		q->stats.forced_mark++;
> +		/* Non-ECT packet in ECN taildrop mode: queue it. */
>  		break;
>  	}
>  

  reply	other threads:[~2020-03-09 22:12 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-09 18:34 [PATCH net-next 0/6] RED: Introduce an ECN tail-dropping mode Ido Schimmel
2020-03-09 18:34 ` [PATCH net-next 1/6] selftests: qdiscs: Add TDC test for RED Ido Schimmel
2020-03-10 15:40   ` Roman Mashak
2020-03-10 16:56     ` Petr Machata
2020-03-10 17:28       ` Roman Mashak
2020-03-09 18:34 ` [PATCH net-next 2/6] net: sched: Add centralized RED flag checking Ido Schimmel
2020-03-09 22:18   ` Jakub Kicinski
2020-03-10  9:48     ` Petr Machata
2020-03-10 19:53       ` Jakub Kicinski
2020-03-10 22:23         ` Petr Machata
2020-03-10 23:00           ` Jakub Kicinski
2020-03-10 23:53             ` Petr Machata
2020-03-09 18:35 ` [PATCH net-next 3/6] net: sched: RED: Introduce an ECN tail-dropping mode Ido Schimmel
2020-03-09 22:12   ` Jakub Kicinski [this message]
2020-03-10  9:48     ` Petr Machata
2020-03-09 18:35 ` [PATCH net-next 4/6] mlxsw: spectrum_qdisc: Offload RED " Ido Schimmel
2020-03-09 18:35 ` [PATCH net-next 5/6] selftests: qdiscs: RED: Add taildrop tests Ido Schimmel
2020-03-09 18:35 ` [PATCH net-next 6/6] selftests: mlxsw: RED: Test RED ECN taildrop offload Ido Schimmel

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