netdev - Re: [PATCH bpf-next v4 1/2] bpf, xdp: make bpf_redirect

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Message-ID: <87sg5jys8r.fsf@toke.dk>
Date:   Fri, 26 Feb 2021 12:37:40 +0100
From:   Toke Høiland-Jørgensen <toke@...hat.com>
To:     Björn Töpel <bjorn.topel@...il.com>,
        ast@...nel.org, daniel@...earbox.net, netdev@...r.kernel.org,
        bpf@...r.kernel.org
Cc:     Björn Töpel <bjorn.topel@...el.com>,
        maciej.fijalkowski@...el.com, hawk@...nel.org,
        magnus.karlsson@...el.com, john.fastabend@...il.com,
        kuba@...nel.org, davem@...emloft.net
Subject: Re: [PATCH bpf-next v4 1/2] bpf, xdp: make bpf_redirect_map() a map
 operation

Björn Töpel <bjorn.topel@...il.com> writes:

> From: Björn Töpel <bjorn.topel@...el.com>
>
> Currently the bpf_redirect_map() implementation dispatches to the
> correct map-lookup function via a switch-statement. To avoid the
> dispatching, this change adds bpf_redirect_map() as a map
> operation. Each map provides its bpf_redirect_map() version, and
> correct function is automatically selected by the BPF verifier.
>
> A nice side-effect of the code movement is that the map lookup
> functions are now local to the map implementation files, which removes
> one additional function call.
>
> Signed-off-by: Björn Töpel <bjorn.topel@...el.com>

Nice! I agree that this is a much nicer approach! :)

(That last paragraph above is why I asked if you updated the performance
numbers in the cover letter; removing an additional function call should
affect those, right?)

Acked-by: Toke Høiland-Jørgensen <toke@...hat.com>