netdev - RE: [PATCH v2 bpf-next 03/14] libbpf: support CO-RE relocations for multi-prog sections

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Message-ID: <5f4f385de8cd3_5f39820863@john-XPS-13-9370.notmuch>
Date:   Tue, 01 Sep 2020 23:14:53 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     Andrii Nakryiko <andriin@...com>, bpf@...r.kernel.org,
        netdev@...r.kernel.org, ast@...com, daniel@...earbox.net
Cc:     andrii.nakryiko@...il.com, kernel-team@...com,
        Andrii Nakryiko <andriin@...com>
Subject: RE: [PATCH v2 bpf-next 03/14] libbpf: support CO-RE relocations for
 multi-prog sections

Andrii Nakryiko wrote:
> Fix up CO-RE relocation code to handle relocations against ELF sections
> containing multiple BPF programs. This requires lookup of a BPF program by its
> section name and instruction index it contains. While it could have been done
> as a simple loop, it could run into performance issues pretty quickly, as
> number of CO-RE relocations can be quite large in real-world applications, and
> each CO-RE relocation incurs BPF program look up now. So instead of simple
> loop, implement a binary search by section name + insn offset.
> 
> Signed-off-by: Andrii Nakryiko <andriin@...com>
> ---
>  tools/lib/bpf/libbpf.c | 82 +++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 74 insertions(+), 8 deletions(-)
> 

Acked-by: John Fastabend <john.fastabend@...il.com>