Re: [PATCH v3 2/3] liveupdate: kho: Increase metadata bitmap size to PAGE_SIZE

[David Matlack]

On Mon, Oct 20, 2025 at 5:09 PM Pasha Tatashin
<pasha.tatashin@xxxxxxxxxx> wrote:
>
> KHO memory preservation metadata is preserved in 512 byte chunks which
> requires their allocation from slab allocator. Slabs are not safe to be
> used with KHO because of kfence, and because partial slabs may lead
> leaks to the next kernel. Change the size to be PAGE_SIZE.

> -#define PRESERVE_BITS (512 * 8)
> +#define PRESERVE_BITS (PAGE_SIZE * 8)

nit: A comment somewhere (maybe here?) about the requirement that KHO
metadata are not stored on slabs would be helpful to avoid someone
"optimizing" this back to 512 in the future.