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From: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: bpf <bpf@vger.kernel.org>, "Alexei Starovoitov" <ast@kernel.org>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Andrii Nakryiko" <andrii@kernel.org>,
	"Martin KaFai Lau" <kafai@fb.com>,
	"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
	"Jesper Dangaard Brouer" <brouer@redhat.com>,
	"Toke Høiland-Jørgensen" <toke@redhat.com>,
	Networking <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next v4 06/11] libbpf: Support kernel module function calls
Date: Sat, 25 Sep 2021 05:24:17 +0530	[thread overview]
Message-ID: <20210924235417.eqhzbrajwkenk6rd@apollo.localdomain> (raw)
In-Reply-To: <CAEf4BzaZOv5c=-hs4UX3UcqP-fFkv8ABx5FAWXRMCDE8-vZ9Lg@mail.gmail.com>

On Wed, Sep 22, 2021 at 04:11:13AM IST, Andrii Nakryiko wrote:
> On Mon, Sep 20, 2021 at 7:15 AM Kumar Kartikeya Dwivedi
> <memxor@gmail.com> wrote:
> > [...]
> > +                       return -E2BIG;
> > +               }
> > +               ext->ksym.offset = index;
>
> > +       } else {
> > +               ext->ksym.offset = 0;
> >         }
>
> I think it will be cleaner if you move the entire offset determination
> logic after all the other checks are performed and ext is mostly
> populated. That will also make the logic shorter and simpler because
> if ayou find kern_btf_fd match, you can exit early (or probably rather

Ack to everything else (including the other mail), but...

> goto to report the match and exit). Otherwise
>

This sentence got eaten up.

> >
> >         kern_func = btf__type_by_id(kern_btf, kfunc_id);
>
> this is actually extremely wasteful for module BTFs. Let's add
> internal (at least for now) helper that will search only for "own" BTF
> types in the BTF, skipping types in base BTF. Something like
> btf_type_by_id_own()?
>

Just to make sure I am not misunderstanding: I don't see where this is wasteful.
btf_type_by_id seems to not be searching anything, but just returns pointer in
base BTF if kfunc_id < btf->start_id, otherwise in module BTF.

What am I missing? I guess the 'kern_btf' name was the source of confusion? If
so, I'll rename it.

Thanks.

--
Kartikeya

  reply	other threads:[~2021-09-24 23:54 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-20 14:15 [PATCH bpf-next v4 00/11] Support kernel module function calls from eBPF Kumar Kartikeya Dwivedi
2021-09-20 14:15 ` [PATCH bpf-next v4 01/11] bpf: Introduce BPF support for kernel module function calls Kumar Kartikeya Dwivedi
2021-09-20 14:15 ` [PATCH bpf-next v4 02/11] bpf: Be conservative while processing invalid kfunc calls Kumar Kartikeya Dwivedi
2021-09-20 14:15 ` [PATCH bpf-next v4 03/11] bpf: btf: Introduce helpers for dynamic BTF set registration Kumar Kartikeya Dwivedi
2021-09-20 14:15 ` [PATCH bpf-next v4 04/11] tools: Allow specifying base BTF file in resolve_btfids Kumar Kartikeya Dwivedi
2021-09-20 14:15 ` [PATCH bpf-next v4 05/11] bpf: Enable TCP congestion control kfunc from modules Kumar Kartikeya Dwivedi
2021-09-21 22:18   ` Andrii Nakryiko
2021-09-21 22:23     ` Kumar Kartikeya Dwivedi
2021-09-21 23:02       ` Andrii Nakryiko
2021-09-20 14:15 ` [PATCH bpf-next v4 06/11] libbpf: Support kernel module function calls Kumar Kartikeya Dwivedi
2021-09-21 22:41   ` Andrii Nakryiko
2021-09-24 23:54     ` Kumar Kartikeya Dwivedi [this message]
2021-09-25  0:30       ` Andrii Nakryiko
2021-09-20 14:15 ` [PATCH bpf-next v4 07/11] libbpf: Resolve invalid weak kfunc calls with imm = 0, off = 0 Kumar Kartikeya Dwivedi
2021-09-21 22:47   ` Andrii Nakryiko
2021-09-20 14:15 ` [PATCH bpf-next v4 08/11] libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations Kumar Kartikeya Dwivedi
2021-09-21  0:57   ` Alexei Starovoitov
2021-09-21  4:50     ` Kumar Kartikeya Dwivedi
2021-09-21 19:04       ` Alexei Starovoitov
2021-09-21 22:25         ` Kumar Kartikeya Dwivedi
2021-09-20 14:15 ` [PATCH bpf-next v4 09/11] tools: bpftool: Add separate fd_array map support for light skeleton Kumar Kartikeya Dwivedi
2021-09-20 14:15 ` [PATCH bpf-next v4 10/11] libbpf: Fix skel_internal.h to set errno on loader retval < 0 Kumar Kartikeya Dwivedi
2021-09-20 14:15 ` [PATCH bpf-next v4 11/11] bpf: selftests: Add selftests for module kfunc support Kumar Kartikeya Dwivedi
2021-09-21 23:00   ` Andrii Nakryiko
2021-09-21 23:13     ` Kumar Kartikeya Dwivedi
2021-09-21 23:28       ` Kumar Kartikeya Dwivedi
2021-09-22  0:03       ` Andrii Nakryiko
2021-09-22  6:06         ` Kumar Kartikeya Dwivedi
2021-09-22 18:24           ` Alexei Starovoitov
2021-09-21  0:29 ` [PATCH bpf-next v4 00/11] Support kernel module function calls from eBPF Andrii Nakryiko
2021-09-21  4:55   ` Kumar Kartikeya Dwivedi

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