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Date:   Thu, 27 Jul 2023 13:26:53 +0100
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Subject: Re: [RFC PATCH 3/5] libbpf, bpftool: Support BPF_PROG_TYPE_OOM_POLICY
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To:     Chuyi Zhou <zhouchuyi@bytedance.com>, hannes@cmpxchg.org,
        mhocko@kernel.org, roman.gushchin@linux.dev, ast@kernel.org,
        daniel@iogearbox.net, andrii@kernel.org
Cc:     bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        wuyun.abel@bytedance.com, robin.lu@bytedance.com
References: <20230727073632.44983-1-zhouchuyi@bytedance.com>
 <20230727073632.44983-4-zhouchuyi@bytedance.com>
From:   Quentin Monnet <quentin@isovalent.com>
In-Reply-To: <20230727073632.44983-4-zhouchuyi@bytedance.com>
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2023-07-27 15:36 UTC+0800 ~ Chuyi Zhou <zhouchuyi@bytedance.com>
> Support BPF_PROG_TYPE_OOM_POLICY program in libbpf and bpftool, so that
> we can identify and use BPF_PROG_TYPE_OOM_POLICY in our application.
> 
> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
> ---
>  tools/bpf/bpftool/common.c     |  1 +
>  tools/include/uapi/linux/bpf.h | 14 ++++++++++++++
>  tools/lib/bpf/libbpf.c         |  3 +++
>  tools/lib/bpf/libbpf_probes.c  |  2 ++
>  4 files changed, 20 insertions(+)
> 
> diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
> index cc6e6aae2447..c5c311299c4a 100644
> --- a/tools/bpf/bpftool/common.c
> +++ b/tools/bpf/bpftool/common.c
> @@ -1089,6 +1089,7 @@ const char *bpf_attach_type_input_str(enum bpf_attach_type t)
>  	case BPF_TRACE_FENTRY:			return "fentry";
>  	case BPF_TRACE_FEXIT:			return "fexit";
>  	case BPF_MODIFY_RETURN:			return "mod_ret";
> +	case BPF_OOM_POLICY:			return "oom_policy";

This case is not necessary. This block is here to keep legacy attach
type strings supported by bpftool. In your case, the name is the same as
the one provided by libbpf, so...

>  	case BPF_SK_REUSEPORT_SELECT:		return "sk_skb_reuseport_select";
>  	case BPF_SK_REUSEPORT_SELECT_OR_MIGRATE:	return "sk_skb_reuseport_select_or_migrate";
>  	default:	return libbpf_bpf_attach_type_str(t);

... we just want to pick it up from libbpf directly, here.

[...]

> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 214f828ece6b..10496bb9b3bc 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -118,6 +118,7 @@ static const char * const attach_type_name[] = {
>  	[BPF_TRACE_KPROBE_MULTI]	= "trace_kprobe_multi",
>  	[BPF_STRUCT_OPS]		= "struct_ops",
>  	[BPF_NETFILTER]			= "netfilter",
> +	[BPF_OOM_POLICY]		= "oom_policy",
>  };