From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
dwarves@vger.kernel.org, bpf <bpf@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andriin@fb.com>, Yonghong Song <yhs@fb.com>,
Hao Luo <haoluo@google.com>
Subject: Re: [RFC/PATCH 1/3] btf_encoder: Generate also .init functions
Date: Thu, 12 Nov 2020 11:37:45 -0800 [thread overview]
Message-ID: <CAEf4BzbdysbGSvJRBZDN=R82KOSgQ8qm_6TDGMhEP3Pvg1RQSw@mail.gmail.com> (raw)
In-Reply-To: <20201112150506.705430-2-jolsa@kernel.org>
On Thu, Nov 12, 2020 at 7:05 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Currently we skip functions under .init* sections, Removing the .init*
> section check, BTF now contains also functions from .init* sections.
>
> Andrii's explanation from email:
>
> > ... I think we should just drop the __init check and
> > include all the __init functions into BTF. There could be cases where
> > we'd need to attach BPF programs to __init functions (e.g., bpf_lsm
> > security cases), so having BTFs for those FUNCs are necessary as well.
> > Ftrace currently disallows that, but it's only because no user-space
> > application has a way to attach probes early enough. This might change
> > in the future, so there is no need to invent special mechanisms now
> > for bpf_iter function preservation. Let's just include all __init
> > functions in BTF.
>
> It's over ~2000 functions on my .config:
>
> $ bpftool btf dump file ./vmlinux | grep 'FUNC ' | wc -l
> 41505
> $ bpftool btf dump file /sys/kernel/btf/vmlinux | grep 'FUNC ' | wc -l
> 39256
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
Looks good.
Acked-by: Andrii Nakryiko <andrii@kernel.org>
> btf_encoder.c | 43 ++-----------------------------------------
> 1 file changed, 2 insertions(+), 41 deletions(-)
>
[...]
next prev parent reply other threads:[~2020-11-12 19:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 15:05 [RFC 0/3] btf_encoder: Fix functions BTF data generation Jiri Olsa
2020-11-12 15:05 ` [RFC/PATCH 1/3] btf_encoder: Generate also .init functions Jiri Olsa
2020-11-12 19:37 ` Andrii Nakryiko [this message]
2020-11-12 15:05 ` [RFC/PATCH 2/3] btf_encoder: Put function generation code to generate_func Jiri Olsa
2020-11-12 19:39 ` Andrii Nakryiko
2020-11-12 15:05 ` [RFC/PATCH 3/3] btf_encoder: Func generation fix Jiri Olsa
2020-11-12 19:54 ` Andrii Nakryiko
2020-11-12 21:14 ` Jiri Olsa
2020-11-13 0:08 ` Andrii Nakryiko
2020-11-13 0:18 ` Alexei Starovoitov
2020-11-13 0:30 ` Andrii Nakryiko
2020-11-13 1:00 ` Yonghong Song
2020-11-13 1:12 ` Andrii Nakryiko
2020-11-13 10:59 ` Jiri Olsa
2020-11-13 11:52 ` Arnaldo Carvalho de Melo
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