Re: [PATCH] elf: Make _dl_sort_maps prefer default DFS algorithm

On 13/08/26 09:16, litenglong wrote:
> The default dynamic_sort tunable is 2, which maps to
> dso_sort_algorithm_dfs.  Update the likely branch to match the
> default, without changing behavior for valid tunable values.

What does this change really gain here? I am inclined to avoid this kind of
code churn.

> 
> Reviewed-by: gaoxiang<[email protected]>
> ---
>  elf/dl-sort-maps.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/elf/dl-sort-maps.c b/elf/dl-sort-maps.c
> index 28ba850a6b..75e6fc1015 100644
> --- a/elf/dl-sort-maps.c
> +++ b/elf/dl-sort-maps.c
> @@ -303,8 +303,8 @@ _dl_sort_maps (struct link_map **maps, unsigned int nmaps,
>       PTR_MANGLE/DEMANGLE, further impairing performance of small, common
>       input cases. A simple if-case with direct function calls appears to
>       be the fastest.  */
> -  if (__glibc_likely (GLRO(dl_dso_sort_algo) == dso_sort_algorithm_original))
> -    _dl_sort_maps_original (maps, nmaps, force_first, for_fini);
> -  else
> +  if (__glibc_likely (GLRO(dl_dso_sort_algo) == dso_sort_algorithm_dfs))
>      _dl_sort_maps_dfs (maps, nmaps, force_first, for_fini);
> +  else
> +    _dl_sort_maps_original (maps, nmaps, force_first, for_fini);
>  }