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On Thu, 2024-02-15 at 10:11 -0500, Jon Maloy wrote:
I wonder if the following could be acceptable:
if (flags & MSG_PEEK)
sk_peek_offset_fwd(sk, used);
else if (peek_offset > 0)
sk_peek_offset_bwd(sk, used);
peek_offset is already present in the data cache, and if it has the value
zero it means either that that sk->sk_peek_off is unused (-1) or actually is zero.
Either way, no rewind is needed in that case.
I agree the above should avoid touching cold cachelines in the
fastpath, and looks functionally correct to me.
The last word is up to Eric :)