[RFC PATCH v3 12/37] Docs/admin-guide/mm/damon/usage: document sample primitives dir

SeongJae Park
2025-12-08T06:30:08Z

Update DAMON usage document for the selective access sampling primitives
activation, which is essential for using page fault events as the access
check sampling primitive.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
Documentation/admin-guide/mm/damon/usage.rst | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index 7da4c002cb39..897a89950351 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -65,6 +65,7 @@ comma (",").
│ │ │ │ │ :ref:`monitoring_attrs <sysfs_monitoring_attrs>`/
│ │ │ │ │ │ intervals/sample_us,aggr_us,update_us
│ │ │ │ │ │ │ intervals_goal/access_bp,aggrs,min_sample_us,max_sample_us
+ │ │ │ │ │ │ sample/primitives/page_table,page_faults
│ │ │ │ │ │ nr_regions/min,max
│ │ │ │ │ :ref:`targets <sysfs_targets>`/nr_targets
│ │ │ │ │ │ :ref:`0 <sysfs_target>`/pid_target,obsolete_target
@@ -215,9 +216,9 @@ contexts/<N>/monitoring_attrs/
------------------------------

Files for specifying attributes of the monitoring including required quality
-and efficiency of the monitoring are in ``monitoring_attrs`` directory.
-Specifically, two directories, ``intervals`` and ``nr_regions`` exist in this
-directory.
+and efficiency of the monitoring, and types of accesses to monitor are in
+``monitoring_attrs`` directory. Specifically, three directories, ``intervals``
+, ``nr_regions`` and ``sample`` exist in this directory.

Under ``intervals`` directory, three files for DAMON's sampling interval
(``sample_us``), aggregation interval (``aggr_us``), and update interval
@@ -232,6 +233,18 @@ writing to and rading from the files.
For more details about the intervals and monitoring regions range, please refer
to the Design document (:doc:`/mm/damon/design`).

+Under ``sample`` directory, a directory, ``primitives`` exists.
+
+contexts/<N>/monitoring_attrs/sample/primitives/
+------------------------------------------------
+
+This directory is for the access sampling primitives :ref:`selection
+<damon_design_sampling_primitives_selection>`. Under ``primitives`` directory,
+two files, ``page_table`` and ``page_faults`` exist. By writing ``Y`` or ``N``
+to these files, users can select whether to use the :ref:`page table accessed
+bit <damon_design_pte_accessed_bit_access_check>` and :ref:`page fault events
+<damon_design_page_fault_access_check>`, respectively.
+
.. _damon_usage_sysfs_monitoring_intervals_goal:

contexts/<N>/monitoring_attrs/intervals/intervals_goal/
--
2.47.3