[RFC PATCH v5 06/11] Docs/admin-guide/mm/damon/usage: document fail_charge_{num,denom} files

SeongJae Park
2026-04-10T14:21:01Z

Update DAMON usage document for the DAMOS action failed regions quota
charge ratio control sysfs files.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
Documentation/admin-guide/mm/damon/usage.rst | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index bfdb717441f05..d5548e460857c 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -84,7 +84,9 @@ comma (",").
│ │ │ │ │ │ │ │ sz/min,max
│ │ │ │ │ │ │ │ nr_accesses/min,max
│ │ │ │ │ │ │ │ age/min,max
- │ │ │ │ │ │ │ :ref:`quotas <sysfs_quotas>`/ms,bytes,reset_interval_ms,effective_bytes,goal_tuner
+ │ │ │ │ │ │ │ :ref:`quotas <sysfs_quotas>`/ms,bytes,reset_interval_ms,
+ │ │ │ │ │ │ │ effective_bytes,goal_tuner,
+ │ │ │ │ │ │ │ fail_charge_num,fail_charge_denom
│ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
│ │ │ │ │ │ │ │ :ref:`goals <sysfs_schemes_quota_goals>`/nr_goals
│ │ │ │ │ │ │ │ │ 0/target_metric,target_value,current_value,nid,path
@@ -381,9 +383,10 @@ schemes/<N>/quotas/
The directory for the :ref:`quotas <damon_design_damos_quotas>` of the given
DAMON-based operation scheme.

-Under ``quotas`` directory, five files (``ms``, ``bytes``,
-``reset_interval_ms``, ``effective_bytes`` and ``goal_tuner``) and two
-directories (``weights`` and ``goals``) exist.
+Under ``quotas`` directory, seven files (``ms``, ``bytes``,
+``reset_interval_ms``, ``effective_bytes``, ``goal_tuner``, ``fail_charge_num``
+and ``fail_charge_denom``) and two directories (``weights`` and ``goals``)
+exist.

You can set the ``time quota`` in milliseconds, ``size quota`` in bytes, and
``reset interval`` in milliseconds by writing the values to the three files,
@@ -402,6 +405,13 @@ the background design of the feature and the name of the selectable algorithms.
Refer to :ref:`goals directory <sysfs_schemes_quota_goals>` for the goals
setup.

+You can set the action-failed memory quota charging ratio by writing the
+numerator and the denominator for the ratio to ``fail_charge_num`` and
+``fail_charge_denom`` files, respectively. Reading those files will return the
+current set values. Refer to :ref:`design
+<damon_design_damos_quotas_failed_memory_charging_ratio>` for more details of
+the ratio feature.
+
The time quota is internally transformed to a size quota. Between the
transformed size quota and user-specified size quota, smaller one is applied.
Based on the user-specified :ref:`goal <sysfs_schemes_quota_goals>`, the
--
2.47.3