[PATCH 3/4] elf: align ET_DYN base to exec folio order for contpte mapping

[WANG Rui]

Hi Usama,

Glad to see you're pushing on this, I'm also following it. I first noticed this when rustc's perf regressed after a binutils upgrade. I'm trying to make ld.so to aware THP and adjust PT_LOAD alignment to increase the chances of shared libraries being mapped by THP [1]. As you're probably seen, I'm doing something similar in the kernel to improve it for executables [2].

> +			if (exec_folio_order())
> +				alignment = max(alignment,
> +					(unsigned long)PAGE_SIZE << exec_folio_order());

I’m curious, does it make sense to add some constraints here, like only increasing p_align when the segment length, virtual address, and file offset are all huge-aligned, as I did in my patch? This has come up several times in the glibc review, where increasing alignment was noted to reduce ASLR entropy.

[1] https://sourceware.org/pipermail/libc-alpha/2026-March/175776.html
[2] https://lore.kernel.org/linux-fsdevel/20260313005211.882831-1-r@hev.cc

Thanks,
Rui