People sometimes get confused about the purposes of DAMON
special-purpose modules and sample modules.  Clarify those on the design
document by adding a section describing their existence and purposes.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/mm/damon/design.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index f3db943d7efc..da0bc40c2261 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -836,3 +836,16 @@ modules for proactive reclamation and LRU lists manipulation are provided.  For
 more detail, please read the usage documents for those
 (:doc:`/admin-guide/mm/damon/reclaim` and
 :doc:`/admin-guide/mm/damon/lru_sort`).
+
+
+Sample DAMON Modules
+--------------------
+
+DAMON modules that provides example DAMON kernel API usages.
+
+kernel programmers can build their own special or general purpose DAMON modules
+using DAMON kernel API.  To help them easily understand how DAMON kernel API
+can be used, a few sample modules are provided under ``samples/damon/`` of the
+linux source tree.  Please note that these modules are not developed for being
+used on real products, but only for showing how DAMON kernel API can be used in
+simple ways.
-- 
2.47.3