Re: [PATCH v2 2/2] docs: clarify THP admin guide about (File|Shmem)PmdMapped and ShmemHugePage

[David Hildenbrand]

On 04.04.25 12:01, Pankaj Raghav (Samsung) wrote:
> From: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
>
> Move FilePmdMapped to previous paragraph for clarity, and clarify
> ShmemPmdMapped & ShmemHugePage.
>
> Signed-off-by: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
> ---
>   Documentation/admin-guide/mm/transhuge.rst | 16 ++++++++++------
>   1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst
> index 01b7ce90d693..b0b9d578732b 100644
> --- a/Documentation/admin-guide/mm/transhuge.rst
> +++ b/Documentation/admin-guide/mm/transhuge.rst
> @@ -465,13 +465,17 @@ AnonHugePmdMapped).
>   
>   The number of PMD-sized transparent huge pages currently used by
>   filesystem data (page cache) is available by reading the FileHugePages field
> -in ``/proc/meminfo``.
> +in ``/proc/meminfo``. The number of these huge pages that are mapped to userspace
> +is available by reading FilePmdMapped field in ``proc/meminfo``. To identify
> +what applications are mapping these huge pages, it is necessary to read
> +``/proc/PID/smaps`` and count the FilePmdMapped fields for each mapping.
>   

Having that change here looks weird.

I suggest to just squash both patches, they are intertwined.

> -The number of file transparent huge pages mapped to userspace is available
> -by reading ShmemPmdMapped and ShmemHugePages fields in ``/proc/meminfo``.
> -To identify what applications are mapping file transparent huge pages, it
> -is necessary to read ``/proc/PID/smaps`` and count the FilePmdMapped fields
> -for each mapping.
> +The number of PMD-sized transparent huge pages currently used by
> +tmpfs/shmem is available by reading the ShmemHugePages field
> +in ``/proc/meminfo``. The number of these huge pages that are mapped to userspace
> +is available by reading ShmemPmdMapped field in ``proc/meminfo``. To identify
> +what applications are mapping these huge pages, it is necessary to read
> +``/proc/PID/smaps`` and count the ShmemPmdMapped fields for each mapping.

Apart from that (and taking Bagas comment in account), LGTM.

Feel free to add

Acked-by: David Hildenbrand <david@xxxxxxxxxx>

--
Cheers,

David / dhildenb