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
