netdev - [PATCH v3 net-next 08/14] net_sched: sch_fq: move qdisc_bstats_update() to fq_dequeue

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Message-ID: <20251121083256.674562-9-edumazet@google.com>
Date: Fri, 21 Nov 2025 08:32:50 +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 v3 net-next 08/14] net_sched: sch_fq: move qdisc_bstats_update()
 to fq_dequeue_skb()

Group together changes to qdisc fields to reduce chances of false sharing
if another cpu attempts to acquire the qdisc spinlock.

  qdisc_qstats_backlog_dec(sch, skb);
  sch->q.qlen--;
  qdisc_bstats_update(sch, skb);

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 net/sched/sch_fq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index fee922da2f99c0c7ac6d86569cf3bbce47898951..0b0ca1aa9251f959e87dd5dc504fbe0f4cbc75eb 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -497,6 +497,7 @@ static void fq_dequeue_skb(struct Qdisc *sch, struct fq_flow *flow,
 	skb_mark_not_on_list(skb);
 	qdisc_qstats_backlog_dec(sch, skb);
 	sch->q.qlen--;
+	qdisc_bstats_update(sch, skb);
 }
 
 static void flow_queue_add(struct fq_flow *flow, struct sk_buff *skb)
@@ -776,7 +777,6 @@ static struct sk_buff *fq_dequeue(struct Qdisc *sch)
 		f->time_next_packet = now + len;
 	}
 out:
-	qdisc_bstats_update(sch, skb);
 	return skb;
 }
 
-- 
2.52.0.460.gd25c4c69ec-goog