Document the new DAMON_LRU_SORT parameter, filter_young_pages.  It can
be used to use page level access re-check for the LRU sorting.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 Documentation/admin-guide/mm/damon/lru_sort.rst | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/admin-guide/mm/damon/lru_sort.rst b/Documentation/admin-guide/mm/damon/lru_sort.rst
index 7b0775d281b4..18fa73a59f62 100644
--- a/Documentation/admin-guide/mm/damon/lru_sort.rst
+++ b/Documentation/admin-guide/mm/damon/lru_sort.rst
@@ -79,6 +79,20 @@ of parametrs except ``enabled`` again.  Once the re-reading is done, this
 parameter is set as ``N``.  If invalid parameters are found while the
 re-reading, DAMON_LRU_SORT will be disabled.
 
+filter_young_pages
+------------------
+
+Filter [none-]young pages accordingly for LRU [de]prioritizations.
+
+If this is set, check page level access (youngness) once again before each
+LRU [de]prioritization operation.  LRU prioritization operation is skipped
+if the page has not accessed since the last check (not young).  LRU
+deprioritization operation is skipped if the page has accessed since the
+last check (young).  The feature is enabled or disabled if this parameter is
+set as ``Y`` or ``N``, respectively.
+
+Disabled by default.
+
 hot_thres_access_freq
 ---------------------
 
-- 
2.39.5