Re: [PATCH v5 0/3] Use BTF to trim return values

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Wed, 2 Sep 2026 11:25:29 +0800
Peng Donglin <dolinux.peng@gmail.com> wrote:

> >>    - Do not print a return value for functions with a void return type.
> >>    - Trim integer, enum, struct, and union values to the available return
> >>      value width when the BTF type provides suitable size information.
> >>    - Format integer, enum, and boolean values according to their BTF
> >>      encoding.
> >>    - Mark values as "(trunc)" when the return type is wider than the
> >>      value captured by the function graph tracer.
> > 
> > Hmm, I really don't like the "(trunc)" If it's the real return type, then
> > it should just print what the real size is. No need to state it was truncated.
> 
> Thanks, I agree. We can remove the "(trunc)" suffix and print the actual 
> type information instead, for example:
> 
>      ret=0x5[struct:0x10]
> 
> This would indicate that the return type is a struct with a size of 0x10 
> bytes.

Hmm, shouldn't both the actually applied size and the true size be displayed?
e.g.

ret=0x5 (in 8 bytes, true size: 16 bytes)

Thank you,

> 
> Would this be acceptable?
> 
> > 

-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>