Re: [PATCH 5/7] mm: add new 'orders' parameter for find_get_entries() and find_lock_entries()

[Matthew Wilcox]

On Thu, Jun 06, 2024 at 07:58:55PM +0800, Baolin Wang wrote:
> In the following patches, shmem will support the swap out of large folios,
> which means the shmem mappings may contain large order swap entries, so an
> 'orders' array is added for find_get_entries() and find_lock_entries() to
> obtain the order size of shmem swap entries, which will help in the release
> of shmem large folio swap entries.

I am not a fan.  I was hoping that 'order' would be encoded in the swap
entry, not passed as a separate parameter.

As I understand it, we currently have a free bit, or
swp_to_radix_entry() would not work.  We can use that as detailed
here to encode the order in a single bit.

https://kernelnewbies.org/MatthewWilcox/NaturallyAlignedOrder