From: Song Liu <song@kernel.org>
To: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
Yonghong Song <yhs@fb.com>,
dwarves@vger.kernel.org, bpf <bpf@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andriin@fb.com>, Hao Luo <haoluo@google.com>,
"Frank Ch. Eigler" <fche@redhat.com>,
Mark Wielaard <mjw@redhat.com>
Subject: Re: [PATCH 1/3] bpf: Move iterator functions into special init section
Date: Wed, 4 Nov 2020 17:01:50 -0800 [thread overview]
Message-ID: <CAPhsuW70S8HmoRFtgzc=r_pBF16kp+E20iaW6awO8TuSfGgYig@mail.gmail.com> (raw)
In-Reply-To: <20201104215923.4000229-2-jolsa@kernel.org>
On Wed, Nov 4, 2020 at 2:02 PM Jiri Olsa <jolsa@kernel.org> wrote:
>
> With upcoming changes to pahole, that change the way how and
> which kernel functions are stored in BTF data, we need a way
> to recognize iterator functions.
>
> Iterator functions need to be in BTF data, but have no real
> body and are currently placed in .init.text section, so they
> are freed after kernel init and are filtered out of BTF data
> because of that.
>
> The solution is to place these functions under new section:
> .init.bpf.preserve_type
>
> And add 2 new symbols to mark that area:
> __init_bpf_preserve_type_begin
> __init_bpf_preserve_type_end
>
> The code in pahole responsible for picking up the functions will
> be able to recognize functions from this section and add them to
> the BTF data and filter out all other .init.text functions.
>
> Suggested-by: Yonghong Song <yhs@fb.com>
> Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: Song Liu <songliubraving@fb.com>
[...]
next prev parent reply other threads:[~2020-11-05 1:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-04 21:59 [PATCHv3 0/3] pahole/kernel: Workaround dwarf bug for function encoding Jiri Olsa
2020-11-04 21:59 ` [PATCH 1/3] bpf: Move iterator functions into special init section Jiri Olsa
2020-11-05 1:01 ` Song Liu [this message]
2020-11-04 21:59 ` [PATCH 2/3] btf_encoder: Move find_all_percpu_vars in generic collect_symbols Jiri Olsa
2020-11-05 19:34 ` Andrii Nakryiko
2020-11-04 21:59 ` [PATCH 3/3] btf_encoder: Change functions check due to broken dwarf Jiri Olsa
2020-11-05 19:52 ` Andrii Nakryiko
2020-11-05 22:56 ` Jiri Olsa
2020-11-06 22:25 [PATCHv4 0/3] pahole/kernel: Workaround dwarf bug for function encoding Jiri Olsa
2020-11-06 22:25 ` [PATCH 1/3] bpf: Move iterator functions into special init section Jiri Olsa
2020-11-09 18:05 ` Arnaldo Carvalho de Melo
2020-11-09 18:06 ` Arnaldo Carvalho de Melo
2020-11-09 18:10 ` Arnaldo Carvalho de Melo
2020-11-09 18:49 ` Jiri Olsa
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