Subject: Re: [PATCH net-next v2 3/4] bpf-timestamp: keep track of the skb when wait_for_space occurs

From: Martin KaFai Lau <[email-masked]>
Date: Wed, 8 Apr 2026 11:12:22 -0700

On Wed, Apr 08, 2026 at 11:15:09AM -0400, Willem de Bruijn wrote:
> > Avoiding adding a new one makes the whole work extremely hard. I'm
> > wondering since we have hwtstamp in shared info, why not add a
> > software one for timestamping use? Then, we would support more
> > different protocols in more different stages in a finer grain, which
> > is a big coarse picture in my mind.
> 
> I don't understand the need to store more data in the skb for BPF.

Adding a field specific to bpf timestamping is not scalable.
There will always be other bpf use cases that need to store
something in a skb.

There have been discussions about storing metadata for a skb which should
solve the general bpf use cases.

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> 
> With BPF hooks, the bpf program can record the relevant data directly
> in a BPF map.