[PATCH 09/12] Docs/mm/damon/design: update for max_nr_snapshots

SeongJae Park
2025-12-16T08:01:59Z

Update DAMON design document for the newly added snapshot level DAMOS
deactivation feature, max_nr_snapshots.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
Documentation/mm/damon/design.rst | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 5cc7b7d662be..7fd819b8bbf7 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -720,6 +720,7 @@ scheme's execution.
- ``qt_exceeds``: Total number of times the quota of the scheme has exceeded.
- ``nr_snapshots``: Total number of DAMON snapshots that the scheme is tried to
be applied.
+- ``max_nr_snapshots``: Upper limit of ``nr_snapshots``.

"A scheme is tried to be applied to a region" means DAMOS core logic determined
the region is eligible to apply the scheme's :ref:`action
@@ -741,6 +742,10 @@ to exclude anonymous pages and the region has only anonymous pages, or if the
action is ``pageout`` while all pages of the region are unreclaimable, applying
the action to the region will fail.

+Unlike normal stats, ``max_nr_snapshots`` is set by users. If it is set as
+non-zero and ``nr_snapshots`` be same to or greater than ``nr_snapshots``, the
+scheme is deactivated.
+
To know how user-space can read the stats via :ref:`DAMON sysfs interface
<sysfs_interface>`, refer to :ref:s`stats <sysfs_stats>` part of the
documentation.
--
2.47.3