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From:   Lorenz Bauer <lmb@isovalent.com>
Date:   Wed, 21 Jun 2023 09:01:15 +0100
Message-ID: <CAN+4W8iSA0Y8iEvYg79=CTNvwkQB5qs_F3vjE7vep-eHR01oJw@mail.gmail.com>
Subject: Re: [PATCH bpf-next v2 3/6] net: remove duplicate reuseport_lookup functions
To:     Kuniyuki Iwashima <kuniyu@amazon.com>
Cc:     andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org,
        daniel@iogearbox.net, davem@davemloft.net, dsahern@kernel.org,
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On Tue, Jun 20, 2023 at 7:31=E2=80=AFPM Kuniyuki Iwashima <kuniyu@amazon.co=
m> wrote:
>
> Good point.  This is based on an assumption that all SO_REUSEPORT
> sockets have the same score, which is wrong for two corner cases
> if reuseport_has_conns() =3D=3D true :
>
>   1) SO_INCOMING_CPU is set
>      -> selected sk might have +1 score
>
>   2) BPF prog returns ESTABLISHED and/or SO_INCOMING_CPU sk
>      -> selected sk will have more than 8
>
> Using the old score could trigger more lookups depending on the
> order that sockets are created.

So the result will still be correct, but it's less performant? Happy
to fix a perf regression, but if the result is incorrect this might
need a separate fix?

Best
Lorenz