From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
Alexei Starovoitov <ast@fb.com>, bpf <bpf@vger.kernel.org>,
Networking <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next] libbpf: Add bpf_object__rodata getter function
Date: Fri, 27 Mar 2020 19:39:44 +0100 [thread overview]
Message-ID: <875zepmykv.fsf@toke.dk> (raw)
In-Reply-To: <CAEf4BzbRpJsoXb3Bvx0_jKGj4gLk-dhXRqryfO23qMreG2B+Kg@mail.gmail.com>
Andrii Nakryiko <andrii.nakryiko@gmail.com> writes:
>> > But basically, why can't you use BPF skeleton?
>>
>> Couple of reasons:
>>
>> - I don't need any of the other features of the skeleton
>> - I don't want to depend on bpftool in the build process
>> - I don't want to embed the BPF bytecode into the C object
>
> Just curious, how are you intending to use global variables. Are you
> restricting to a single global var (a struct probably), so it's easier
> to work with it? Or are you resolving all the variables' offsets
> manually? It's really inconvenient to work with global variables
> without skeleton, which is why I'm curious.
Yeah, there's a single:
static volatile const struct xdp_dispatcher_config conf = {};
in the BPF file. Which is defined as:
struct xdp_dispatcher_config {
__u8 num_progs_enabled;
__u32 chain_call_actions[MAX_DISPATCHER_ACTIONS];
};
>> > Also, application can already find that map by looking at name.
>>
>> Yes, it can find the map, but it can't access the data. But I guess I
>> could just add a getter for that. Just figured this was easier to
>> consume; but I can see why it might impose restrictions on future
>> changes, so I'll send a v2 with such a map-level getter instead.
>
> Sounds good, I'll go review v2 now.
Great, thanks!
-Toke
next prev parent reply other threads:[~2020-03-27 18:39 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 15:17 [PATCH bpf-next] libbpf: Add bpf_object__rodata getter function Toke Høiland-Jørgensen
2020-03-26 19:20 ` Andrii Nakryiko
2020-03-27 12:24 ` Toke Høiland-Jørgensen
2020-03-27 17:49 ` Andrii Nakryiko
2020-03-27 18:39 ` Toke Høiland-Jørgensen [this message]
2020-03-27 12:58 ` [PATCH bpf-next v2] libbpf: Add getter for pointer to data area for internal maps Toke Høiland-Jørgensen
2020-03-27 19:17 ` Andrii Nakryiko
2020-03-27 22:26 ` Toke Høiland-Jørgensen
2020-03-27 22:28 ` Alexei Starovoitov
2020-03-28 0:08 ` Toke Høiland-Jørgensen
2020-03-28 18:28 ` [PATCH v3 1/2] libbpf: Add setter for initial value " Toke Høiland-Jørgensen
2020-03-28 20:01 ` Andrii Nakryiko
2020-03-29 12:17 ` Toke Høiland-Jørgensen
2020-03-29 13:22 ` [PATCH v4 " Toke Høiland-Jørgensen
2020-03-29 20:06 ` Andrii Nakryiko
2020-03-29 23:46 ` Daniel Borkmann
2020-03-29 13:22 ` [PATCH v4 2/2] selftests: Add test for overriding global data value before load Toke Høiland-Jørgensen
2020-03-29 20:13 ` Andrii Nakryiko
2020-03-28 18:28 ` [PATCH v3 " Toke Høiland-Jørgensen
2020-03-28 20:06 ` Andrii Nakryiko
2020-03-29 13:10 ` Toke Høiland-Jørgensen
2020-03-29 20:08 ` Andrii Nakryiko
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