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net_sched: sch_fq: tweak unlikely() hints in fq_dequeue()

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After 076433bd78 ("net_sched: sch_fq: add fast path
for mostly idle qdisc") we need to remove one unlikely()
because q->internal holds all the fast path packets.

       skb = fq_peek(&q->internal);
       if (unlikely(skb)) {
                q->internal.qlen--;

Calling INET_ECN_set_ce() is very unlikely.

These changes allow fq_dequeue_skb() to be (auto)inlined,
thus making fq_dequeue() faster.

$ scripts/bloat-o-meter -t vmlinux.0 vmlinux
add/remove: 2/2 grow/shrink: 0/1 up/down: 283/-269 (14)
Function                                     old     new   delta
INET_ECN_set_ce                                -     267    +267
__pfx_INET_ECN_set_ce                          -      16     +16
__pfx_fq_dequeue_skb                          16       -     -16
fq_dequeue_skb                               103       -    -103
fq_dequeue                                  1685    1535    -150
Total: Before=24886569, After=24886583, chg +0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20260203214716.880853-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-02-03 21:47:16 +00:00 committed by Jakub Kicinski
parent f8a062b255
commit acd21dd2da
1 changed files with 2 additions and 2 deletions
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4
net/sched/sch_fq.c
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@ -665,7 +665,7 @@ static struct sk_buff *fq_dequeue(struct Qdisc *sch)
return NULL;
skb = fq_peek(&q->internal);
if (unlikely(skb)) {
if (skb) {
q->internal.qlen--;
fq_dequeue_skb(sch, &q->internal, skb);
goto out;
@ -716,7 +716,7 @@ static struct sk_buff *fq_dequeue(struct Qdisc *sch)
}
prefetch(&skb->end);
fq_dequeue_skb(sch, f, skb);
if ((s64)(now - time_next_packet - q->ce_threshold) > 0) {
if (unlikely((s64)(now - time_next_packet - q->ce_threshold) > 0)) {
INET_ECN_set_ce(skb);
q->stat_ce_mark++;
}