On Thu, Feb 15, 2024 at 6:41 PM Paolo Abeni
<pabeni(a)redhat.com> wrote:
Note: please send text-only email to netdev.
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 :)
An actual patch seems needed.
In the current form, local variable peek_offset is 0 when !MSG_PEEK.
So the "else if (peek_offset > 0)" would always be false.