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| author | Eric Dumazet <edumazet@google.com> | 2016-06-21 23:16:49 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-06-25 12:19:35 -0400 |
| commit | 520ac30f45519b0a82dd92117c181d1d6144677b (patch) | |
| tree | a3189ae1ab3b5be6213716e42ddaec082578e774 /net/sched/sch_drr.c | |
| parent | 36195d869e4b1dbf81bafa3a31bb095a3c013bdd (diff) | |
| download | linux-stable-520ac30f45519b0a82dd92117c181d1d6144677b.tar.gz linux-stable-520ac30f45519b0a82dd92117c181d1d6144677b.tar.bz2 linux-stable-520ac30f45519b0a82dd92117c181d1d6144677b.zip | |
net_sched: drop packets after root qdisc lock is released
Qdisc performance suffers when packets are dropped at enqueue()
time because drops (kfree_skb()) are done while qdisc lock is held,
delaying a dequeue() draining the queue.
Nominal throughput can be reduced by 50 % when this happens,
at a time we would like the dequeue() to proceed as fast as possible.
Even FQ is vulnerable to this problem, while one of FQ goals was
to provide some flow isolation.
This patch adds a 'struct sk_buff **to_free' parameter to all
qdisc->enqueue(), and in qdisc_drop() helper.
I measured a performance increase of up to 12 %, but this patch
is a prereq so that future batches in enqueue() can fly.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_drr.c')
| -rw-r--r-- | net/sched/sch_drr.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c index 22609e4e845f..8af5c59eef84 100644 --- a/net/sched/sch_drr.c +++ b/net/sched/sch_drr.c @@ -350,7 +350,8 @@ static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch, return NULL; } -static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch) +static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch, + struct sk_buff **to_free) { struct drr_sched *q = qdisc_priv(sch); struct drr_class *cl; @@ -360,11 +361,11 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch) if (cl == NULL) { if (err & __NET_XMIT_BYPASS) qdisc_qstats_drop(sch); - kfree_skb(skb); + __qdisc_drop(skb, to_free); return err; } - err = qdisc_enqueue(skb, cl->qdisc); + err = qdisc_enqueue(skb, cl->qdisc, to_free); if (unlikely(err != NET_XMIT_SUCCESS)) { if (net_xmit_drop_count(err)) { cl->qstats.drops++; |