On 2026-03-04 10:56:16 [-0500], Willem de Bruijn wrote:

Sebastian Andrzej Siewior wrote:

quoted

Would it be okay if I occupy three bits in sk_buff which look unused?

Have you looked into using skb_extensions?

Yes. I would have allocate memory via __skb_ext_alloc() and attach it to
the skb via __skb_ext_set(). That would on receive and while sending
(via af_packet).
Looking at the current allocations as of skb_ext_type_len, they all need
a bit of memory, the smallest is mctp_flow with just a pointer the other
are a fair amount larger. For the three bits, I was hoping to avoid it.

Sebastian