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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>
This commit is contained in:
Dave Taht 2019-08-03 16:37:29 -07:00 committed by David S. Miller
parent ae697f3bf7
commit 77ddaff218
1 changed files with 1 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
net/sched/sch_fq_codel.c
View File

@ -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;