Re: [PATCH v5 18/22] docs: add documentation for memfd preservation via LUO

Pasha Tatashin
2025-11-13T16:56:04Z

> +Limitations
> +===========
> +
> +The current implementation has the following limitations:
> +
> +Size
> + Currently the size of the file is limited by the size of the FDT. The FDT can
> + be at of most ``MAX_PAGE_ORDER`` order. By default this is 4 MiB with 4K
> + pages. Each page in the file is tracked using 16 bytes. This limits the
> + maximum size of the file to 1 GiB.

The above should be removed, as we are using KHO vmalloc that resolves
this limitation. Pratyush, I suggest for v6 let's move memfd
documnetation right into the code: memfd_luo.c and
liveupdate/abi/memfd.h, and source it from there.

Keeping documentation with the code helps reduce code/doc divergence.

Pasha