Re: [PATCH v5 6/7] btf: Add lazy sorting validation for binary search

[Eduard Zingerman <eddyz87@gmail.com>]

On Mon, 2025-11-10 at 09:42 +0800, Donglin Peng wrote:

[...]

> [[Resending in plain text format - previous HTML email was rejected]
> 
> Thanks for the feedback. Based on the previous discussions, I plan
> to implement the following changes in the next version:
> 
> 1. Modify the btf__permute interface to adopt the ID map approach, as
>     suggested by Andrii.
> 
> 2. Remove the lazy sort check and move the verification to the BTF
>     parsing phase. This addresses two concerns: potential race conditions
>     with write operations and const-cast issues. The overhead is negligible
>      (approximately 1.4ms for vmlinux BTF).
> 
> 3. Invoke the btf__permute interface to implement BTF sorting in resolve_btfids.
> 
> I welcome any further suggestions.

Hi Donglin,

I think this summarizes the discussion pretty well.
One thing to notice about (2): if sorting is done by resolve_btfids,
there is no need to check for BTF being sorted in vmlinux BTF.
So, maybe it's a good idea to skip this check for it, as Alexei suggested
(but not for programs BTF).

Thanks,
Eduard.