Re: [PATCH v2] tracing: Point constant hist field type to string literal

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

On Wed, 27 May 2026 10:34:50 +0800
Yu Peng <pengyu@kylinos.cn> wrote:

> The HIST_FIELD_FL_CONST path uses the fixed "u64" type string.
> 
> Point hist_field->type directly to the string literal, matching the
> HIST_FIELD_FL_HITCOUNT path. The release path already uses kfree_const(),
> so no duplication is needed.
> 
> Signed-off-by: Yu Peng <pengyu@kylinos.cn>

This looks good to me.

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

Thanks,

> ---
> Changes in v2:
> - Point hist_field->type directly to "u64" as suggested.
> 
>  kernel/trace/trace_events_hist.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index eb2c2bc8bc3d5..b50f2bd5ff771 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -1992,9 +1992,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
>  	if (flags & HIST_FIELD_FL_CONST) {
>  		hist_field->fn_num = HIST_FIELD_FN_CONST;
>  		hist_field->size = sizeof(u64);
> -		hist_field->type = kstrdup("u64", GFP_KERNEL);
> -		if (!hist_field->type)
> -			goto free;
> +		hist_field->type = "u64";
>  		goto out;
>  	}
>  
> -- 
> 2.43.0


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