netdev - Re: [PATCH bpf-next v4 09/27] bpf: Add support to load multi func tracing program

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Message-ID: <CAEf4BzYJXJbquSKdc_iEfFGXuA3eYMgwvAbOWEkBo7BW4faZww@mail.gmail.com>
Date:   Tue, 31 Aug 2021 16:17:33 -0700
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     Jiri Olsa <jolsa@...hat.com>
Cc:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andriin@...com>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...omium.org>, Daniel Xu <dxu@...uu.xyz>,
        Viktor Malik <vmalik@...hat.com>
Subject: Re: [PATCH bpf-next v4 09/27] bpf: Add support to load multi func
 tracing program

On Thu, Aug 26, 2021 at 12:40 PM Jiri Olsa <jolsa@...hat.com> wrote:
>
> Adding support to load tracing program with new BPF_F_MULTI_FUNC flag,
> that allows the program to be loaded without specific function to be
> attached to.

Are there any benefits to using a new load flag vs having separate
expected attach types like FENTRY_MULTI/FEXIT_MULTI? I find load flags
a bigger pain to work with compared to expected attach type (and
expected attach type should be more apparent in BPF link info, bpftool
output, etc).

>
> Such program will be allowed to be attached to multiple functions
> in following patches.
>
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  include/linux/bpf.h            |  1 +
>  include/uapi/linux/bpf.h       |  7 +++++++
>  kernel/bpf/syscall.c           | 35 +++++++++++++++++++++++++++++-----
>  kernel/bpf/verifier.c          |  3 ++-
>  tools/include/uapi/linux/bpf.h |  7 +++++++
>  5 files changed, 47 insertions(+), 6 deletions(-)
>

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