From: David Ahern <dsahern@gmail.com>
To: "Jesper Dangaard Brouer" <brouer@redhat.com>,
"Maciej Żenczykowski" <maze@google.com>
Cc: bpf <bpf@vger.kernel.org>, Linux NetDev <netdev@vger.kernel.org>,
Daniel Borkmann <borkmann@iogearbox.net>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Lorenz Bauer <lmb@cloudflare.com>,
Shaun Crampton <shaun@tigera.io>,
Lorenzo Bianconi <lorenzo@kernel.org>,
Marek Majkowski <marek@cloudflare.com>,
John Fastabend <john.fastabend@gmail.com>,
Jakub Kicinski <kuba@kernel.org>,
David Ahern <dsahern@kernel.org>
Subject: Re: [PATCH bpf-next V1 2/6] bpf: bpf_fib_lookup return MTU value as output when looked up
Date: Wed, 7 Oct 2020 09:38:56 -0700 [thread overview]
Message-ID: <23e087e7-066c-2228-8df7-3a6b81ad2ba0@gmail.com> (raw)
In-Reply-To: <20201007094228.5919998b@carbon>
On 10/7/20 12:42 AM, Jesper Dangaard Brouer wrote:
>
> The struct bpf_fib_lookup is exactly 1 cache-line (64 bytes) for
> performance reasons. I do believe that it can be extended, as Ahern
> designed the BPF-helper API cleverly via a plen (detail below signature).
Yes, I kept it to 64B for performance reasons which is why most fields
have 1 value on input and another on output.
Technically it can be extended, but any cost in doing so should be
abosrbed by the new feature(s). Meaning, users just doing a fib lookup
based on current API should not take a hit with the extra size.
next prev parent reply other threads:[~2020-10-07 16:38 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 16:02 [PATCH bpf-next V1 0/6] bpf: New approach for BPF MTU handling and enforcement Jesper Dangaard Brouer
2020-10-06 16:02 ` [PATCH bpf-next V1 1/6] bpf: Remove MTU check in __bpf_skb_max_len Jesper Dangaard Brouer
2020-10-06 16:02 ` [PATCH bpf-next V1 2/6] bpf: bpf_fib_lookup return MTU value as output when looked up Jesper Dangaard Brouer
2020-10-07 1:34 ` Maciej Żenczykowski
2020-10-07 7:42 ` Jesper Dangaard Brouer
2020-10-07 16:38 ` David Ahern [this message]
2020-10-07 7:28 ` kernel test robot
2020-10-06 16:03 ` [PATCH bpf-next V1 3/6] bpf: add BPF-helper for reading MTU from net_device via ifindex Jesper Dangaard Brouer
2020-10-06 16:33 ` Jesper Dangaard Brouer
2020-10-07 1:18 ` Jakub Kicinski
2020-10-07 1:24 ` Maciej Żenczykowski
2020-10-07 7:53 ` Jesper Dangaard Brouer
2020-10-07 16:35 ` David Ahern
2020-10-07 17:44 ` Maciej Żenczykowski
2020-10-06 16:03 ` [PATCH bpf-next V1 4/6] bpf: make it possible to identify BPF redirected SKBs Jesper Dangaard Brouer
2020-10-06 16:03 ` [PATCH bpf-next V1 5/6] bpf: Add MTU check for TC-BPF packets after egress hook Jesper Dangaard Brouer
2020-10-06 20:09 ` kernel test robot
2020-10-07 0:26 ` kernel test robot
2020-10-06 16:03 ` [PATCH bpf-next V1 6/6] bpf: drop MTU check when doing TC-BPF redirect to ingress Jesper Dangaard Brouer
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