From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Daniel Xu <dxu@dxuuu.xyz>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>, Martin Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
Andrii Nakryiko <andriin@fb.com>,
john fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
bpf <bpf@vger.kernel.org>, Networking <netdev@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH bpf-next] libbpf: Export bpf_object__load_vmlinux_btf
Date: Tue, 26 May 2020 22:09:11 -0700 [thread overview]
Message-ID: <CAEf4BzbR+7X-boCBC-f60jugp8xWKVTeFTyUmrcv8Qy4iKsvjg@mail.gmail.com> (raw)
In-Reply-To: <20200527015704.2294223-1-dxu@dxuuu.xyz>
On Tue, May 26, 2020 at 7:09 PM Daniel Xu <dxu@dxuuu.xyz> wrote:
>
> Right now the libbpf model encourages loading the entire object at once.
> In this model, libbpf handles loading BTF from vmlinux for us. However,
> it can be useful to selectively load certain maps and programs inside an
> object without loading everything else.
There is no way to selectively load or not load a map. All maps are
created, unless they are reusing map FD or pinned instances. See
below, I'd like to understand the use case better.
>
> In the latter model, there was perviously no way to load BTF on-demand.
> This commit exports the bpf_object__load_vmlinux_btf such that we are
> able to load BTF on demand.
>
Let's start with the real problem, not a solution. Do you have
specific use case where you need bpf_object__load_vmlinux_btf()? It
might not do anything if none of BPF programs in the object requires
BTF, because it's very much tightly coupled with loading bpf_object as
a whole model. I'd like to understand what you are after with this,
before exposing internal implementation details as an API.
> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
> ---
> tools/lib/bpf/libbpf.c | 2 +-
> tools/lib/bpf/libbpf.h | 1 +
> tools/lib/bpf/libbpf.map | 1 +
> 3 files changed, 3 insertions(+), 1 deletion(-)
>
[...]
next prev parent reply other threads:[~2020-05-27 5:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 1:57 [PATCH bpf-next] libbpf: Export bpf_object__load_vmlinux_btf Daniel Xu
2020-05-27 5:09 ` Andrii Nakryiko [this message]
2020-05-27 17:03 ` Daniel Xu
2020-05-27 21:33 ` Andrii Nakryiko
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