From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7A4D63AA4F1; Sat, 17 Oct 2026 16:35:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254904; cv=none; b=qb+KFzRhCtuLRuHFCpEDmj9irYWxcIHmFWxJwLxXkSLg52bd3lR0E257HOENRzW/0V/Z2zlVf+yXn3BVz4PPFYm9VlZTQLb70wNR456D6wrn9Q9cxeRoQxI4Our4uX+AJabt0NGyZ4vn/h9ZGxdSTYnx07Dhxq6tVnwO1evLa7I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254904; c=relaxed/simple; bh=+BcTQ139Q966FJOaGy8mnHoFx/x6nQ8HpyuINuQIZ6c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dUauIQHnL2ld9dVPSlCEW5e0dyJNeWmBQ0LhedgEE6mq76C0piuqaV5eKjwP3k3pDRHS2MzQNh/Yxbi1L+oLJknJQwMkz8Gv0BAp72HJik809dypAvOBTiePV1XeGWV6sejzo5hu9PofbzGC7qmp9G1bXGR7xa2etghNbY3YmVY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hRKL77qo; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="hRKL77qo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5F6B1F000C6; Sat, 17 Oct 2026 16:35:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792254903; bh=2FP6wr2LRI+8grclvEvXXg2TpGghv1xwl4EDRApUo58=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=hRKL77qouOvfvjfF369wVNUuNEZzJWY+ZiZ2FWcnfSRwRPn+FCMViBf4jXQUwmvIx qqX2RwJYJbPDm3bimT96/0OYlD9bKlqwFcSroDPvbWJT5nHdKSyl69bGeCKnoxEyJJ vawy5oSpbAlerF0gccSOCTvL2bS1/JtCc4FpRSas= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Victor Nogueira , =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Jamal Hadi Salim , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 598/869] net_sched: sch_fq: add three drop_reason Date: Sat, 17 Oct 2026 17:57:19 +0200 Message-ID: <20261017160052.376712508@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 5765c7f6e3173eb894889a29963a497aeb721c5e ] Add three new drop_reason, more precise than generic QDISC_DROP: "tc -s qd" show aggregate counters, it might be more useful to use drop_reason infrastructure for bug hunting. 1) SKB_DROP_REASON_FQ_BAND_LIMIT Whenever a packet is added while its band limit is hit. Corresponding value in "tc -s qd" is bandX_drops XXXX 2) SKB_DROP_REASON_FQ_HORIZON_LIMIT Whenever a packet has a timestamp too far in the future. Corresponding value in "tc -s qd" is horizon_drops XXXX 3) SKB_DROP_REASON_FQ_FLOW_LIMIT Whenever a flow has reached its limit. Corresponding value in "tc -s qd" is flows_plimit XXXX Tested: tc qd replace dev eth1 root fq flow_limit 10 limit 100000 perf record -a -e skb:kfree_skb sleep 1; perf script udp_stream 12329 [004] 216.929492: skb:kfree_skb: skbaddr=0xffff888eabe17e00 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_FLOW_LIMIT udp_stream 12385 [006] 216.929593: skb:kfree_skb: skbaddr=0xffff888ef8827f00 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_FLOW_LIMIT udp_stream 12389 [005] 216.929871: skb:kfree_skb: skbaddr=0xffff888ecb9ba500 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_FLOW_LIMIT udp_stream 12316 [009] 216.930398: skb:kfree_skb: skbaddr=0xffff888eca286b00 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_FLOW_LIMIT udp_stream 12400 [008] 216.930490: skb:kfree_skb: skbaddr=0xffff888eabf93d00 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_FLOW_LIMIT tc qd replace dev eth1 root fq flow_limit 100 limit 10000 perf record -a -e skb:kfree_skb sleep 1; perf script udp_stream 18074 [001] 1058.318040: skb:kfree_skb: skbaddr=0xffffa23c881fc000 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_BAND_LIMIT udp_stream 18126 [005] 1058.320651: skb:kfree_skb: skbaddr=0xffffa23c6aad4000 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_BAND_LIMIT udp_stream 18118 [006] 1058.321065: skb:kfree_skb: skbaddr=0xffffa23df0d48a00 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_BAND_LIMIT udp_stream 18074 [001] 1058.321126: skb:kfree_skb: skbaddr=0xffffa23c881ffa00 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_BAND_LIMIT udp_stream 15815 [003] 1058.321224: skb:kfree_skb: skbaddr=0xffffa23c9835db00 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x9d9 reason: FQ_BAND_LIMIT tc -s -d qd sh dev eth1 qdisc fq 8023: root refcnt 257 limit 10000p flow_limit 100p buckets 1024 orphan_mask 1023 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 weights 589824 196608 65536 quantum 18Kb initial_quantum 92120b low_rate_threshold 550Kbit refill_delay 40ms timer_slack 10us horizon 10s horizon_drop Sent 492439603330 bytes 336953991 pkt (dropped 61724094, overlimits 0 requeues 4463) backlog 14611228b 9995p requeues 4463 flows 2965 (inactive 1151 throttled 0) band0_pkts 0 band1_pkts 9993 band2_pkts 0 gc 6347 highprio 0 fastpath 30 throttled 5 latency 2.32us flows_plimit 7403693 band1_drops 54320401 Signed-off-by: Eric Dumazet Reviewed-by: Victor Nogueira Reviewed-by: Toke Høiland-Jørgensen Acked-by: Jamal Hadi Salim Link: https://patch.msgid.link/20241204171950.89829-1-edumazet@google.com Signed-off-by: Jakub Kicinski Stable-dep-of: 5b483f7791b0 ("net/sched: act_ife: Only operate on Ethernet frames") Signed-off-by: Sasha Levin --- include/net/dropreason-core.h | 18 ++++++++++++++++++ include/net/sch_generic.h | 8 ++++++++ net/sched/sch_fq.c | 14 ++++++++++---- 3 files changed, 36 insertions(+), 4 deletions(-) diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h index f8f4d2b77e6ac..31e0cc1b64ff1 100644 --- a/include/net/dropreason-core.h +++ b/include/net/dropreason-core.h @@ -60,6 +60,9 @@ FN(TC_EGRESS) \ FN(SECURITY_HOOK) \ FN(QDISC_DROP) \ + FN(FQ_BAND_LIMIT) \ + FN(FQ_HORIZON_LIMIT) \ + FN(FQ_FLOW_LIMIT) \ FN(CPU_BACKLOG) \ FN(XDP) \ FN(TC_INGRESS) \ @@ -316,6 +319,21 @@ enum skb_drop_reason { * failed to enqueue to current qdisc) */ SKB_DROP_REASON_QDISC_DROP, + /** + * @SKB_DROP_REASON_FQ_BAND_LIMIT: dropped by fq qdisc when per band + * limit is reached. + */ + SKB_DROP_REASON_FQ_BAND_LIMIT, + /** + * @SKB_DROP_REASON_FQ_HORIZON_LIMIT: dropped by fq qdisc when packet + * timestamp is too far in the future. + */ + SKB_DROP_REASON_FQ_HORIZON_LIMIT, + /** + * @SKB_DROP_REASON_FQ_FLOW_LIMIT: dropped by fq qdisc when a flow + * exceeds its limits. + */ + SKB_DROP_REASON_FQ_FLOW_LIMIT, /** * @SKB_DROP_REASON_CPU_BACKLOG: failed to enqueue the skb to the per CPU * backlog queue. This can be caused by backlog queue full (see diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index d174283373470..016d9cf827069 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -1320,6 +1320,14 @@ static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch, return NET_XMIT_DROP; } +static inline int qdisc_drop_reason(struct sk_buff *skb, struct Qdisc *sch, + struct sk_buff **to_free, + enum skb_drop_reason reason) +{ + tcf_set_drop_reason(skb, reason); + return qdisc_drop(skb, sch, to_free); +} + static inline int qdisc_drop_all(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) { diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c index d06e12d16b0e5..cf70468b67607 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -535,6 +535,8 @@ static bool fq_packet_beyond_horizon(const struct sk_buff *skb, return unlikely((s64)skb->tstamp > (s64)(now + q->horizon)); } +#define FQDR(reason) SKB_DROP_REASON_FQ_##reason + static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) { @@ -546,7 +548,8 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch, band = fq_prio2band(q->prio2band, skb->priority & TC_PRIO_MAX); if (unlikely(q->band_pkt_count[band] >= sch->limit)) { q->stat_band_drops[band]++; - return qdisc_drop(skb, sch, to_free); + return qdisc_drop_reason(skb, sch, to_free, + FQDR(BAND_LIMIT)); } now = ktime_get_ns(); @@ -556,8 +559,9 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch, /* Check if packet timestamp is too far in the future. */ if (fq_packet_beyond_horizon(skb, q, now)) { if (q->horizon_drop) { - q->stat_horizon_drops++; - return qdisc_drop(skb, sch, to_free); + q->stat_horizon_drops++; + return qdisc_drop_reason(skb, sch, to_free, + FQDR(HORIZON_LIMIT)); } q->stat_horizon_caps++; skb->tstamp = now + q->horizon; @@ -570,7 +574,8 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch, if (f != &q->internal) { if (unlikely(f->qlen >= q->flow_plimit)) { q->stat_flows_plimit++; - return qdisc_drop(skb, sch, to_free); + return qdisc_drop_reason(skb, sch, to_free, + FQDR(FLOW_LIMIT)); } if (fq_flow_is_detached(f)) { @@ -595,6 +600,7 @@ static int fq_enqueue(struct sk_buff *skb, struct Qdisc *sch, return NET_XMIT_SUCCESS; } +#undef FQDR static void fq_check_throttled(struct fq_sched_data *q, u64 now) { -- 2.53.0