netdev - [PATCH net-next 05/10] net_sched: cake: use qdisc_pkt

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Message-ID: <20251110094505.3335073-6-edumazet@google.com>
Date: Mon, 10 Nov 2025 09:45:00 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>
Cc: Simon Horman <horms@...nel.org>, Jamal Hadi Salim <jhs@...atatu.com>, 
	Cong Wang <xiyou.wangcong@...il.com>, Jiri Pirko <jiri@...nulli.us>, 
	"Toke Høiland-Jørgensen" <toke@...hat.com>, Kuniyuki Iwashima <kuniyu@...gle.com>, 
	Willem de Bruijn <willemb@...gle.com>, netdev@...r.kernel.org, eric.dumazet@...il.com, 
	Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 05/10] net_sched: cake: use qdisc_pkt_segs()

Use new qdisc_pkt_segs() to avoid a cache line miss in cake_enqueue()
for non GSO packets.

cake_overhead() does not have to recompute it.

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/sched/sch_cake.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index 993ce808230fb7d4769c926f6c8368d927f5a45f..312f5b000ffb67d74faf70f26d808e26315b4ab8 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -1398,12 +1398,12 @@ static u32 cake_overhead(struct cake_sched_data *q, const struct sk_buff *skb)
 	const struct skb_shared_info *shinfo = skb_shinfo(skb);
 	unsigned int hdr_len, last_len = 0;
 	u32 off = skb_network_offset(skb);
+	u16 segs = qdisc_pkt_segs(skb);
 	u32 len = qdisc_pkt_len(skb);
-	u16 segs = 1;
 
 	q->avg_netoff = cake_ewma(q->avg_netoff, off << 16, 8);
 
-	if (!shinfo->gso_size)
+	if (segs == 1)
 		return cake_calc_overhead(q, len, off);
 
 	/* borrowed from qdisc_pkt_len_init() */
@@ -1430,12 +1430,6 @@ static u32 cake_overhead(struct cake_sched_data *q, const struct sk_buff *skb)
 			hdr_len += sizeof(struct udphdr);
 	}
 
-	if (unlikely(shinfo->gso_type & SKB_GSO_DODGY))
-		segs = DIV_ROUND_UP(skb->len - hdr_len,
-				    shinfo->gso_size);
-	else
-		segs = shinfo->gso_segs;
-
 	len = shinfo->gso_size + hdr_len;
 	last_len = skb->len - shinfo->gso_size * (segs - 1);
 
@@ -1788,7 +1782,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 	if (unlikely(len > b->max_skblen))
 		b->max_skblen = len;
 
-	if (skb_is_gso(skb) && q->rate_flags & CAKE_FLAG_SPLIT_GSO) {
+	if (qdisc_pkt_segs(skb) > 1 && q->rate_flags & CAKE_FLAG_SPLIT_GSO) {
 		struct sk_buff *segs, *nskb;
 		netdev_features_t features = netif_skb_features(skb);
 		unsigned int slen = 0, numsegs = 0;
-- 
2.51.2.1041.gc1ab5b90ca-goog