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net: sched: run ingress qdisc without locks 

TC classifiers/actions were converted to RCU by John in the series:
http://thread.gmane.org/gmane.linux.network/329739/focus=329739
and many follow on patches.
This is the last patch from that series that finally drops
ingress spin_lock.

Single cpu ingress+u32 performance goes from 22.9 Mpps to 24.5 Mpps.

In two cpu case when both cores are receiving traffic on the same
device and go into the same ingress+u32 the performance jumps
from 4.5 + 4.5 Mpps to 23.5 + 23.5 Mpps

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
hifive-unleashed-5.1
Alexei Starovoitov 2015-04-30 20:14:07 -07:00 committed by David S. Miller
parent a89f96c927
commit 087c1a601a
2 changed files with 3 additions and 4 deletions
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2
net/core/dev.c
View File

@ -3547,10 +3547,8 @@ static int ing_filter(struct sk_buff *skb, struct netdev_queue *rxq)
q = rcu_dereference(rxq->qdisc);
if (q != &noop_qdisc) {
spin_lock(qdisc_lock(q));
if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
result = qdisc_enqueue_root(skb, q);
spin_unlock(qdisc_lock(q));
}
return result;

5
net/sched/sch_ingress.c
View File

@ -65,11 +65,11 @@ static int ingress_enqueue(struct sk_buff *skb, struct Qdisc *sch)
result = tc_classify(skb, fl, &res);
qdisc_bstats_update(sch, skb);
qdisc_bstats_update_cpu(sch, skb);
switch (result) {
case TC_ACT_SHOT:
result = TC_ACT_SHOT;
qdisc_qstats_drop(sch);
qdisc_qstats_drop_cpu(sch);
break;
case TC_ACT_STOLEN:
case TC_ACT_QUEUED:
@ -91,6 +91,7 @@ static int ingress_enqueue(struct sk_buff *skb, struct Qdisc *sch)
static int ingress_init(struct Qdisc *sch, struct nlattr *opt)
{
net_inc_ingress_queue();
sch->flags |= TCQ_F_CPUSTATS;
return 0;
}