Commit 77ddaff2 authored by Dave Taht's avatar Dave Taht Committed by David S. Miller
Browse files

fq_codel: Kill useless per-flow dropped statistic 



It is almost impossible to get anything other than a 0 out of
flow->dropped statistic with a tc class dump, as it resets to 0
on every round.

It also conflates ecn marks with drops.

It would have been useful had it kept a cumulative drop count, but
it doesn't. This patch doesn't change the API, it just stops
tracking a stat and state that is impossible to measure and nobody
uses.

Signed-off-by: default avatarDave Taht <dave.taht@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ae697f3b

net/sched/sch_fq_codel.c

+1 −7
Original line number Diff line number Diff line
@@ -45,7 +45,6 @@ struct fq_codel_flow { 
	struct sk_buff	  *tail;

	struct list_head  flowchain;

	int		  deficit;

	u32		  dropped; /* number of drops (or ECN marks) on this flow */

	struct codel_vars cvars;

}; /* please try to keep this structure <= 64 bytes */
@@ -175,7 +174,6 @@ static unsigned int fq_codel_drop(struct Qdisc *sch, unsigned int max_packets, 


	/* Tell codel to increase its signal strength also */

	flow->cvars.count += i;

	flow->dropped += i;

	q->backlogs[idx] -= len;

	q->memory_usage -= mem;

	sch->qstats.drops += i;
@@ -213,7 +211,6 @@ static int fq_codel_enqueue(struct sk_buff *skb, struct Qdisc *sch, 
		list_add_tail(&flow->flowchain, &q->new_flows);

		q->new_flow_count++;

		flow->deficit = q->quantum;

		flow->dropped = 0;

	}

	get_codel_cb(skb)->mem_usage = skb->truesize;

	q->memory_usage += get_codel_cb(skb)->mem_usage;
@@ -312,9 +309,6 @@ begin: 
			    &flow->cvars, &q->cstats, qdisc_pkt_len,

			    codel_get_enqueue_time, drop_func, dequeue_func);



	flow->dropped += q->cstats.drop_count - prev_drop_count;

	flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;



	if (!skb) {

		/* force a pass through old_flows to prevent starvation */

		if ((head == &q->new_flows) && !list_empty(&q->old_flows))
@@ -660,7 +654,7 @@ static int fq_codel_dump_class_stats(struct Qdisc *sch, unsigned long cl, 
			sch_tree_unlock(sch);

		}

		qs.backlog = q->backlogs[idx];

		qs.drops = flow->dropped;

		qs.drops = 0;

	}

	if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)

		return -1;

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