From: "Björn Töpel" <bjorn.topel@intel.com>
To: Alex Forster <aforster@cloudflare.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Network Development <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
"Karlsson, Magnus" <magnus.karlsson@intel.com>,
bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next] libbpf: fix AF_XDP helper program to support kernels without the JMP32 eBPF instruction class
Date: Fri, 20 Dec 2019 08:20:48 +0100 [thread overview]
Message-ID: <c02dbf12-f1ae-8cb1-13fc-a7bb2fbff3aa@intel.com> (raw)
In-Reply-To: <CAKxSbF19OsyE8B9mM+nB6676R6oA0duXSLn6_GGr1A+tCKhY9w@mail.gmail.com>
On 2019-12-19 23:29, Alex Forster wrote:
>> I though af_xdp landed after jmp32 ?
>
> They were indeed pretty close together, but AF_XDP became usable in
> late 2018 with either 4.18 or 4.19. JMP32 landed in early 2019 with
> 5.1.
>
Correct, but is anyone really using AF_XDP pre-5.1?
The rationale for doing JMP32:
https://lore.kernel.org/bpf/87v9sip0i8.fsf@toke.dk/
I think going forward, a route where different AF_XDP programs is loaded
based on what currently running kernel supports. "Every s^Hcycle is
sacred", and we're actually paying for the extra checks.
Then again, failing to load is still pretty bad. :-) Thanks for fixing this.
Acked-by: Björn Töpel <bjorn.topel@intel.com>
> Alex Forster
>
next prev parent reply other threads:[~2019-12-20 7:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-19 20:16 [PATCH bpf-next] libbpf: fix AF_XDP helper program to support kernels without the JMP32 eBPF instruction class Alex Forster
2019-12-19 22:07 ` Alexei Starovoitov
2019-12-19 22:29 ` Alex Forster
2019-12-20 7:20 ` Björn Töpel [this message]
2019-12-20 20:22 ` Daniel Borkmann
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