Re: [PATCH] Docs/admin-guide/mm/damon/reclaim: document how to disable watermarks

[SJ Park <sj@kernel.org>]

Hello Jinjie,

On Wed, 28 Oct 2026 10:36:28 +0800 Jinjie Ruan <ruanjinjie@huawei.com> wrote:

> DAMON_RECLAIM runs its scheme only while the free memory rate is
> between `wmarks_low` and `wmarks_mid`.
> 
> But some users want to reclaim cold pages even while the system has
> plenty of free memory, and it is not obvious that the existing
> watermarks parameters can already do that. So Document the setup.

Thank you for this patch!

> 
> Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
> ---
>  Documentation/admin-guide/mm/damon/reclaim.rst | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst
> index ec7e3e32b4ac..23fede7d1cdb 100644
> --- a/Documentation/admin-guide/mm/damon/reclaim.rst
> +++ b/Documentation/admin-guide/mm/damon/reclaim.rst
> @@ -193,6 +193,13 @@ DAMON_RECLAIM becomes inactive, so it does nothing but periodically checks the
>  watermarks.  In the case, the system falls back to the LRU-list based page
>  granularity reclamation logic.
>  
> +To keep DAMON_RECLAIM always active regardless of the free memory rate, set
> +``wmarks_high``, ``wmarks_mid`` and ``wmarks_low`` to ``1000``, ``1000`` and
> +``0``, respectively.  Then the reclamation is limited only by ``min_age`` and
> +the quotas.  This is useful for reclaiming cold pages even while the system
> +has plenty of free memory, e.g., right after an idle virtual machine is
> +paused.
> +

I feel like above might be too detailed.  Particularly, the second sentence
looks too detailed.  In a sense, it is not technically correct because of
'skip_anon' parameter.  We might later need to add more such controls, and I
concern if this kind of detailed documentation will limit such extensions.

What about keeping only the first sentence and dropping later two sentences?


Thanks,
SJ

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