Hi Carlos,
the sorting algorithm code portions of the patch has not been updated a lot
for this v4 version, mainly a rebase of v3 to current master.

Here was the v3 version for reference (responded to some v2 issues there).
Unfortunately this one never seemed to got a review, though it seems the
main issues were in the testing infrastructure patch.
https://sourceware.org/pipermail/libc-alpha/2020-July/116546.html

Note that in the attached patch, I still have the old sorting algorithm set as default,
the more "conservative" setting. This can be adjusted if deemed appropriate when patch
is approved.

Tested current master on x86_64-linux with no regressions, seeking approval
for getting this into 2.33.

Thanks,
Chung-Lin

2021-01-03  Chung-Lin Tang  <cltang@codesourcery.com>

	[BZ #17645]
	[BZ #15311]
	[BZ #15310]

	* elf/dl-close.c (_dl_close_worker): Remove used[], done[] char arrays,
	use l_map_used/l_map_done bitfields instead. Adjust call to _dl_sort_maps.
	* elf/dl-deps.c (_dl_map_object_deps): Adjust call to _dl_sort_maps.
	* elf/dl-fini.c (_dl_fini): Likewise.
	* elf/dl-sort_maps.c
	(_dl_sort_maps_original): Adapted from original _dl_sort_maps.
	(dfs_traversal): New static function.
	(_dl_sort_maps_dfs): New Reverse-Postorder (RPO) based implementation.
	(_dl_sort_maps): Select and call either _dl_sort_maps_original or
	_dl_sort_maps_dfs based on glibc.rtld.dynamic_sort.
	* elf/dl-tunables.list (rtld): New namespace with tunable 'dynamic_sort'.
	* include/link.h (struct link_map): Add l_visited:1, l_map_used:1, and
	l_map_done:1 bitfields.
	* sysdeps/generic/ldsodefs.h (_dl_sort_maps): Adjust declaration.