Add three qdisc-specific drop reasons and use them in sch_cake:
1) SKB_DROP_REASON_QDISC_OVERLIMIT
Whenever the total queue limit for a qdisc instance is exceeded
and a packet is dropped to make room.
2) SKB_DROP_REASON_QDISC_CONGESTED
Whenever a packet is dropped by the qdisc AQM algorithm because
congestion is detected.
3) SKB_DROP_REASON_CAKE_FLOOD
Whenever a packet is dropped by the flood protection part of the
CAKE AQM algorithm (BLUE).
Also use the existing SKB_DROP_REASON_QUEUE_PURGE in cake_clear_tin().
Reasons show up as:
perf record -a -e skb:kfree_skb sleep 1; perf script
iperf3 665 [005] 848.656964: skb:kfree_skb: skbaddr=0xffff98168a333500 rx_sk=(nil) protocol=34525 location=__dev_queue_xmit+0x10f0 reason: QDISC_OVERLIMIT
swapper 0 [001] 909.166055: skb:kfree_skb: skbaddr=0xffff98168280cee0 rx_sk=(nil) protocol=34525 location=cake_dequeue+0x5ef reason: QDISC_CONGESTED
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Dave Taht <dave.taht@gmail.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20241211-cake-drop-reason-v2-1-920afadf4d1b@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
a42d71e322