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: Dave Taht <dave.taht@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
index d67b2c4..9edd0f4 100644 (file)
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -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;