Re: [PATCH v2] mm: shmem: Rename mTHP shmem counters

[David Hildenbrand]

On 10.07.24 11:55, Ryan Roberts wrote:
> The legacy PMD-sized THP counters at /proc/vmstat include
> thp_file_alloc, thp_file_fallback and thp_file_fallback_charge, which
> rather confusingly refer to shmem THP and do not include any other types
> of file pages. This is inconsistent since in most other places in the
> kernel, THP counters are explicitly separated for anon, shmem and file
> flavours. However, we are stuck with it since it constitutes a user ABI.
>
> Recently, commit 66f44583f9b6 ("mm: shmem: add mTHP counters for
> anonymous shmem") added equivalent mTHP stats for shmem, keeping the
> same "file_" prefix in the names. But in future, we may want to add
> extra stats to cover actual file pages, at which point, it would all
> become very confusing.
>
> So let's take the opportunity to rename these new counters "shmem_"
> before the change makes it upstream and the ABI becomes immutable. While
> we are at it, let's improve the documentation for the legacy counters to
> make it clear that they count shmem pages only.
>
> Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
> Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
> Reviewed-by: Lance Yang <ioworker0@xxxxxxxxx>
> ---

Acked-by: David Hildenbrand <david@xxxxxxxxxx>

--
Cheers,

David / dhildenb