Docs/admin-guide/mm/damon/usage: document fail_charge_{num,denom} files

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

Link: https://lore.kernel.org/20260428013402.115171-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendan.higgins@linux.dev>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index 534e1199cf0917d9a6c3c2154d3e189aef311bcb..e84b58731f7e3202815088f23de550198feb9b6a 100644 (file)
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -83,7 +83,9 @@ 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
@@ -377,9 +379,10 @@ 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,
@@ -398,6 +401,13 @@ 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