Messages in this thread | | | Date | Mon, 3 Jan 2022 19:01:30 -0700 | Subject | Re: [PATCH v2 net-next 0/3] net: skb: introduce kfree_skb_with_reason() and use it for tcp and udp | From | David Ahern <> |
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On 1/3/22 6:47 PM, Cong Wang wrote: > On Thu, Dec 30, 2021 at 05:32:37PM +0800, menglong8.dong@gmail.com wrote: >> From: Menglong Dong <imagedong@tencent.com> >> >> In this series patch, the interface kfree_skb_with_reason() is >> introduced(), which is used to collect skb drop reason, and pass >> it to 'kfree_skb' tracepoint. Therefor, 'drop_monitor' or eBPF is >> able to monitor abnormal skb with detail reason. >> > > We already something close, __dev_kfree_skb_any(). Can't we unify > all of these?
Specifically?
The 'reason' passed around by those is either SKB_REASON_CONSUMED or SKB_REASON_DROPPED and is used to call kfree_skb vs consume_skb. i.e., this is unrelated to this patch set and goal.
> > >> In fact, this series patches are out of the intelligence of David >> and Steve, I'm just a truck man :/ >> > > I think there was another discussion before yours, which I got involved > as well. > >> Previous discussion is here: >> >> https://lore.kernel.org/netdev/20211118105752.1d46e990@gandalf.local.home/ >> https://lore.kernel.org/netdev/67b36bd8-2477-88ac-83a0-35a1eeaf40c9@gmail.com/ >> >> In the first patch, kfree_skb_with_reason() is introduced and >> the 'reason' field is added to 'kfree_skb' tracepoint. In the >> second patch, 'kfree_skb()' in replaced with 'kfree_skb_with_reason()' >> in tcp_v4_rcv(). In the third patch, 'kfree_skb_with_reason()' is >> used in __udp4_lib_rcv(). >> > > I don't follow all the discussions here, but IIRC it would be nice > if we can provide the SNMP stat code (for instance, TCP_MIB_CSUMERRORS) to > user-space, because those stats are already exposed to user-space, so > you don't have to invent new ones.
Those SNMP macros are not unique and can not be fed into a generic kfree_skb_reason function.
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