From: Eric Dumazet <edumazet@google.com>
Date: Sat, 2 May 2020 19:54:21 -0700
Subject: net_sched: sch_fq: do not call fq_peek() twice per packet
Patch-mainline: v5.8-rc1
Git-commit: c288b0ca86a0a49ad450cf2d76a9a70c2ca9e43f
References: bsc#1176447
This refactors the code to not call fq_peek() from fq_dequeue_head()
since the caller can provide the skb.
Also rename fq_dequeue_head() to fq_dequeue_skb() because 'head' is
a bit vague, given the skb could come from t_root rb-tree.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
net/sched/sch_fq.c | 34 ++++++++++++++++------------------
1 file changed, 16 insertions(+), 18 deletions(-)
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -384,19 +384,17 @@ static void fq_erase_head(struct Qdisc *
}
}
-/* remove one skb from head of flow queue */
-static struct sk_buff *fq_dequeue_head(struct Qdisc *sch, struct fq_flow *flow)
+/* Remove one skb from flow queue.
+ * This skb must be the return value of prior fq_peek().
+ */
+static void fq_dequeue_skb(struct Qdisc *sch, struct fq_flow *flow,
+ struct sk_buff *skb)
{
- struct sk_buff *skb = fq_peek(flow);
-
- if (skb) {
- fq_erase_head(sch, flow, skb);
- skb_mark_not_on_list(skb);
- flow->qlen--;
- qdisc_qstats_backlog_dec(sch, skb);
- sch->q.qlen--;
- }
- return skb;
+ fq_erase_head(sch, flow, skb);
+ skb_mark_not_on_list(skb);
+ flow->qlen--;
+ qdisc_qstats_backlog_dec(sch, skb);
+ sch->q.qlen--;
}
static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
@@ -508,9 +506,11 @@ static struct sk_buff *fq_dequeue(struct
if (!sch->q.qlen)
return NULL;
- skb = fq_dequeue_head(sch, &q->internal);
- if (skb)
+ skb = fq_peek(&q->internal);
+ if (unlikely(skb)) {
+ fq_dequeue_skb(sch, &q->internal, skb);
goto out;
+ }
now = ktime_get_ns();
fq_check_throttled(q, now);
@@ -550,10 +550,8 @@ begin:
INET_ECN_set_ce(skb);
q->stat_ce_mark++;
}
- }
-
- skb = fq_dequeue_head(sch, f);
- if (!skb) {
+ fq_dequeue_skb(sch, f, skb);
+ } else {
head->first = f->next;
/* force a pass through old_flows to prevent starvation */
if ((head == &q->new_flows) && q->old_flows.first) {