Re: [PATCH -tip 2/2] x86/hweight: Use POPCNT when available with X86_NATIVE_CPU option

[David Laight]

On Sun, 30 Mar 2025 18:07:30 +0200
Uros Bizjak <ubizjak@xxxxxxxxx> wrote:

...
> The kernel is currently compiled with -mno-red-zone, gcc-15 introduces
> special "redzone" clobber to disable red-zone in the function that
> includes asm() when/if the kernel starts using redzone.

I really don't understand the point of a stack 'red-zone'.
In any function that contains memory writes the cost of a
'sub $n,%rsp' at the top and corresponding add at the bottom
is surely noise.

	David.