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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Sun, 23 Feb 2020 14:44:31 -0800
Message-ID: <CAADnVQ+QNxFk97fnsY1NL1PQWykdok_ha_KajCc68bRT1BLp2A@mail.gmail.com>
Subject: Re: [PATCH] docs: sysctl/kernel: document BPF entries
To:     Stephen Kitt <steve@sk2.org>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        Andrii Nakryiko <andriin@fb.com>, bpf <bpf@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Fri, Feb 21, 2020 at 10:18 AM Stephen Kitt <steve@sk2.org> wrote:
>
> Based on the implementation in kernel/bpf/syscall.c,
> kernel/bpf/trampoline.c, include/linux/filter.h, and the documentation
> in bpftool-prog.rst.
>
> Signed-off-by: Stephen Kitt <steve@sk2.org>
> ---
>  Documentation/admin-guide/sysctl/kernel.rst | 24 +++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
> index 1c48ab4bfe30..89c70ea7de7c 100644
> --- a/Documentation/admin-guide/sysctl/kernel.rst
> +++ b/Documentation/admin-guide/sysctl/kernel.rst
> @@ -102,6 +102,20 @@ See the ``type_of_loader`` and ``ext_loader_ver`` fields in
>  :doc:`/x86/boot` for additional information.
>
>
> +bpf_stats_enabled
> +=================
> +
> +Controls whether the kernel should collect statistics on BPF programs
> +(total time spent running, number of times run...). Enabling
> +statistics causes a slight reduction in performance on each program
> +run. The statistics can be seen using ``bpftool``.
> +
> += ===================================
> +0 Don't collect statistics (default).
> +1 Collect statistics.
> += ===================================
> +
> +
>  cap_last_cap
>  ============
>
> @@ -1152,6 +1166,16 @@ NMI switch that most IA32 servers have fires unknown NMI up, for
>  example.  If a system hangs up, try pressing the NMI switch.
>
>
> +unprivileged_bpf_disabled
> +=========================
> +
> +Writing 1 to this entry will disabled unprivileged calls to ``bpf()``;

'will disable' ?

It doesn't apply to bpf-next with:
error: sha1 information is lacking or useless
(Documentation/admin-guide/sysctl/kernel.rst).
error: could not build fake ancestor
Patch failed at 0001 docs: sysctl/kernel: Document BPF entries