Re: [TECH TOPIC] Reaching consensus on CONFIG_HIGHMEM phaseout

Linus Torvalds
2025-09-09T22:24:50Z

On Tue, 9 Sept 2025 at 14:39, H. Peter Anvin <hpa@zytor.com> wrote:
>
> 1 GB systems used highmem too, sadly. And 1 GB was the norm for a big chuck of the late 32-bit era.

Well, while on x86 1GB systems did use highmem, they'd typically not
use very much of it.

IOW, they'd have about 900MB as lowmem (ok, I think it was 896MB to be
exact), with something like 120MB highmem.

So they'd either lose a bit of memory, or they'd use the 2G:2G split.

Or - and I think this is the main point - they'd stay on old kernels
like the ancient museum pieces they are.

I'm not convinced it makes sense to have a modern kernel on a museum piece.

Linus