linux-kernel - Re: [PATCH bpf-next v9 08/10] bpf: Skip anonymous types in type lookup for performance

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Message-ID: <695de859b8af88ddcf53bca22a3ae57d7026b3af.camel@gmail.com>
Date: Tue, 16 Dec 2025 22:55:30 -0800
From: Eduard Zingerman <eddyz87@...il.com>
To: Donglin Peng <dolinux.peng@...il.com>, ast@...nel.org, 
	andrii.nakryiko@...il.com
Cc: zhangxiaoqin@...omi.com, ihor.solodrai@...ux.dev, 
	linux-kernel@...r.kernel.org, bpf@...r.kernel.org, pengdonglin
	 <pengdonglin@...omi.com>, Alan Maguire <alan.maguire@...cle.com>
Subject: Re: [PATCH bpf-next v9 08/10] bpf: Skip anonymous types in type
 lookup for performance

On Mon, 2025-12-08 at 14:23 +0800, Donglin Peng wrote:

[...]

> @@ -550,6 +550,11 @@ u32 btf_nr_types(const struct btf *btf)
>  	return total;
>  }
>  
> +u32 btf_sorted_start_id(const struct btf *btf)
> +{
> +	return btf->sorted_start_id ?: (btf->start_id ?: 1);
> +}
> +

I think that changes in this patch are correct.  However, it seems
error prone to remember that sorted_start_id is always set for
vmlinux/module BTF and might not be set for program BTF.
Wdyt about using the above function everywhere instead of directly
reading the field?

>  /*
>   * Assuming that types are sorted by name in ascending order.
>   */

[...]