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

[SJ Park]

On Tue, 27 Oct 2026 22:24:24 -0700 SJ Park <sj@xxxxxxxxxx> wrote:

> Hello Jinjie,
> 
> On Wed, 28 Oct 2026 10:36:28 +0800 Jinjie Ruan <ruanjinjie@xxxxxxxxxx> 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@xxxxxxxxxx>
> > ---
> >  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?

If you don't mind, I could add this patch to damon/next after dropping the last
two sentences on my own.


Thanks,
SJ

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