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* [PATCH net-next v5 0/4] tun/tap: use kfree_skb_reason() to trace dropped skb
@ 2022-03-04  6:33 Dongli Zhang
  2022-03-04  6:33 ` [PATCH net-next v5 1/4] skbuff: introduce kfree_skb_list_reason() Dongli Zhang
                   ` (4 more replies)
  0 siblings, 5 replies; 7+ messages in thread
From: Dongli Zhang @ 2022-03-04  6:33 UTC (permalink / raw)
  To: netdev, bpf
  Cc: linux-kernel, davem, kuba, rostedt, mingo, ast, daniel, andrii,
	imagedong, joao.m.martins, joe.jin, dsahern, edumazet

The commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()") has
introduced the kfree_skb_reason() to help track the reason.

The tun and tap are commonly used as virtio-net/vhost-net backend. This is to
use kfree_skb_reason() to trace the dropped skb for those two drivers. 

Changed since v1:
- I have renamed many of the reasons since v1. I make them as generic as
  possible so that they can be re-used by core networking and drivers.

Changed since v2:
- declare drop_reason as type "enum skb_drop_reason"
- handle the drop in skb_list_walk_safe() case for tap driver, and
  kfree_skb_list_reason() is introduced

Changed since v3 (only for PATCH 4/4):
- rename to TAP_FILTER and TAP_TXFILTER
- honor reverse xmas tree style declaration for 'drop_reason' in
  tun_net_xmit()

Changed since v4:
- make kfree_skb_list() static inline
- add 'computation' to SKB_CSUM comment
- change COPY_DATA to UCOPY_FAULT
- add 'metadata' to DEV_HDR comment
- expand comment on DEV_READY
- change SKB_TRIM to NOMEM
- chnage SKB_PULL to HDR_TRUNC


The following reasons are introduced.

- SKB_DROP_REASON_SKB_CSUM
- SKB_DROP_REASON_SKB_GSO_SEG
- SKB_DROP_REASON_SKB_UCOPY_FAULT
- SKB_DROP_REASON_DEV_HDR
- SKB_DROP_REASON_FULL_RING
- SKB_DROP_REASON_DEV_READY
- SKB_DROP_REASON_NOMEM
- SKB_DROP_REASON_HDR_TRUNC
- SKB_DROP_REASON_TAP_FILTER
- SKB_DROP_REASON_TAP_TXFILTER


This is the output for TUN device.

# cat /sys/kernel/debug/tracing/trace_pipe
          <idle>-0       [029] ..s1.   450.727651: kfree_skb: skbaddr=0000000023d235cc protocol=0 location=00000000a6748854 reason: NOT_SPECIFIED
          <idle>-0       [000] b.s3.   451.165671: kfree_skb: skbaddr=000000006b5de7cc protocol=4 location=000000007c2b9eae reason: FULL_RING
          <idle>-0       [000] b.s3.   453.149650: kfree_skb: skbaddr=000000006b5de7cc protocol=4 location=000000007c2b9eae reason: FULL_RING
          <idle>-0       [000] b.s3.   455.133576: kfree_skb: skbaddr=000000006b5de7cc protocol=4 location=000000007c2b9eae reason: FULL_RING
          <idle>-0       [000] b.s3.   457.117566: kfree_skb: skbaddr=000000006b5de7cc protocol=4 location=000000007c2b9eae reason: FULL_RING


This is the output for TAP device.

# cat /sys/kernel/debug/tracing/trace_pipe
          arping-7053    [006] ..s1.  1000.047753: kfree_skb: skbaddr=000000008618a587 protocol=2054 location=00000000743ad4a7 reason: FULL_RING
          <idle>-0       [022] ..s1.  1000.778514: kfree_skb: skbaddr=000000002c1e706c protocol=0 location=00000000a6748854 reason: NOT_SPECIFIED
          arping-7053    [006] ..s1.  1001.047830: kfree_skb: skbaddr=000000008618a587 protocol=2054 location=00000000743ad4a7 reason: FULL_RING
          arping-7053    [006] ..s1.  1002.047918: kfree_skb: skbaddr=000000008618a587 protocol=2054 location=00000000743ad4a7 reason: FULL_RING
          arping-7053    [006] ..s1.  1003.048017: kfree_skb: skbaddr=000000008618a587 protocol=2054 location=00000000743ad4a7 reason: FULL_RING



 drivers/net/tap.c          | 35 +++++++++++++++++++++++++----------
 drivers/net/tun.c          | 38 ++++++++++++++++++++++++++++++--------
 include/linux/skbuff.h     | 39 ++++++++++++++++++++++++++++++++++++++-
 include/trace/events/skb.h | 10 ++++++++++
 net/core/skbuff.c          |  7 ++++---
 5 files changed, 107 insertions(+), 22 deletions(-)


Thank you very much!

Dongli Zhang



^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2022-03-04 14:53 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-03-04  6:33 [PATCH net-next v5 0/4] tun/tap: use kfree_skb_reason() to trace dropped skb Dongli Zhang
2022-03-04  6:33 ` [PATCH net-next v5 1/4] skbuff: introduce kfree_skb_list_reason() Dongli Zhang
2022-03-04  6:33 ` [PATCH net-next v5 2/4] net: tap: track dropped skb via kfree_skb_reason() Dongli Zhang
2022-03-04  6:33 ` [PATCH net-next v5 3/4] net: tun: split run_ebpf_filter() and pskb_trim() into different "if statement" Dongli Zhang
2022-03-04  6:33 ` [PATCH net-next v5 4/4] net: tun: track dropped skb via kfree_skb_reason() Dongli Zhang
2022-03-04 12:25 ` [PATCH net-next v5 0/4] tun/tap: use kfree_skb_reason() to trace dropped skb David Miller
2022-03-04 14:52   ` Dongli Zhang

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