Re: [RESEND RFC PATCH v1 15/20] docs: document new procfs ksm knobs

From: Bagas Sanjaya
Date: Mon Jan 23 2023 - 23:09:52 EST


On Mon, Jan 23, 2023 at 09:37:43AM -0800, Stefan Roesch wrote:
> This documents the ksm_process_profit and ksm_merge_type settings in
> ksm_stat.

"Document both ksm_process_profit and ksm_merge_type proc settings."

>
> Signed-off-by: Stefan Roesch <shr@xxxxxxxxxxxx>
> ---
> Documentation/admin-guide/mm/ksm.rst | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst
> index 72189bf1283e..70896f01d641 100644
> --- a/Documentation/admin-guide/mm/ksm.rst
> +++ b/Documentation/admin-guide/mm/ksm.rst
> @@ -211,7 +211,8 @@ several times, which are unprofitable memory consumed.
> ksm_rmap_items * sizeof(rmap_item).
>
> where ksm_merging_pages is shown under the directory ``/proc/<pid>/``,
> - and ksm_rmap_items is shown in ``/proc/<pid>/ksm_stat``.
> + and ksm_rmap_items is shown in ``/proc/<pid>/ksm_stat``. The process profit
> + is also shown in ``/proc/<pid>/ksm_stat`` as ksm_process_profit.
>
> From the perspective of application, a high ratio of ``ksm_rmap_items`` to
> ``ksm_merging_pages`` means a bad madvise-applied policy, so developers or
> @@ -222,6 +223,9 @@ so if the ``ksm_rmap_items/ksm_merging_pages`` ratio exceeds 64 on 64-bit CPU
> or exceeds 128 on 32-bit CPU, then the app's madvise policy should be dropped,
> because the ksm profit is approximately zero or negative.
>
> +The ksm_merge_type in ``/proc/<pid>/ksm_stat`` shows the merge type of the
> +process. Valid values are ``none``, ``madvise`` and ``process``.
> +
> Monitoring KSM events
> =====================
>

The change LGTM.

--
An old man doll... just what I always wanted! - Clara

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