2023-11-30 02:38:34

by SeongJae Park

[permalink] [raw]
Subject: [PATCH 9/9] Docs/admin-guide/mm/damon/usage: document for quota goals

Update DAMON sysfs usage for newly added DAMOS quota goals interface.

Signed-off-by: SeongJae Park <[email protected]>
---
Documentation/admin-guide/mm/damon/usage.rst | 48 +++++++++++++++++---
Documentation/mm/damon/design.rst | 2 +
2 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index da94feb97ed1..ff9f62e65722 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -83,6 +83,8 @@ comma (","). ::
│ │ │ │ │ │ │ │ age/min,max
│ │ │ │ │ │ │ quotas/ms,bytes,reset_interval_ms
│ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
+ │ │ │ │ │ │ │ │ goals/nr_goals
+ │ │ │ │ │ │ │ │ │ 0/target_value,current_value
│ │ │ │ │ │ │ watermarks/metric,interval_us,high,mid,low
│ │ │ │ │ │ │ filters/nr_filters
│ │ │ │ │ │ │ │ 0/type,matching,memcg_id
@@ -113,6 +115,8 @@ details) exists. In the beginning, this directory has only one file,
child directories named ``0`` to ``N-1``. Each directory represents each
kdamond.

+.. _sysfs_kdamond:
+
kdamonds/<N>/
-------------

@@ -121,11 +125,18 @@ In each kdamond directory, two files (``state`` and ``pid``) and one directory

Reading ``state`` returns ``on`` if the kdamond is currently running, or
``off`` if it is not running. Writing ``on`` or ``off`` makes the kdamond be
-in the state. Writing ``commit`` to the ``state`` file makes kdamond reads the
+in the state.
+
+Writing ``commit`` to the ``state`` file makes kdamond reads the
user inputs in the sysfs files except ``state`` file again. Writing
-``update_schemes_stats`` to ``state`` file updates the contents of stats files
-for each DAMON-based operation scheme of the kdamond. For details of the
-stats, please refer to :ref:`stats section <sysfs_schemes_stats>`.
+``commit_schemes_quota_goals`` to the ``state`` file makes kdamond reads the
+DAMON-based operation schemes' :ref:`quota goals <sysfs_schemes_quota_goals>`
+of the kdamond.
+
+Writing ``update_schemes_stats`` to ``state`` file updates the
+contents of stats files for each DAMON-based operation scheme of the kdamond.
+For details of the stats, please refer to :ref:`stats section
+<sysfs_schemes_stats>`.

Writing ``update_schemes_tried_regions`` to ``state`` file updates the
DAMON-based operation scheme action tried regions directory for each
@@ -319,8 +330,7 @@ The directory for the :ref:`quotas <damon_design_damos_quotas>` of the given
DAMON-based operation scheme.

Under ``quotas`` directory, three files (``ms``, ``bytes``,
-``reset_interval_ms``) and one directory (``weights``) having three files
-(``sz_permil``, ``nr_accesses_permil``, and ``age_permil``) in it exist.
+``reset_interval_ms``) and two directores (``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,
@@ -330,11 +340,35 @@ apply the action to only up to ``bytes`` bytes of memory regions within the
``reset_interval_ms``. Setting both ``ms`` and ``bytes`` zero disables the
quota limits.

-You can also set the :ref:`prioritization weights
+Under ``weights`` directory, three files (``sz_permil``,
+``nr_accesses_permil``, and ``age_permil``) exist.
+You can set the :ref:`prioritization weights
<damon_design_damos_quotas_prioritization>` for size, access frequency, and age
in per-thousand unit by writing the values to the three files under the
``weights`` directory.

+.. _sysfs_schemes_quota_goals:
+
+schemes/<N>/quotas/goals/
+-------------------------
+
+The directory for the :ref:`automatic quota tuning goals
+<damon_design_damos_quotas_auto_tuning>` of the given DAMON-based operation
+scheme.
+
+In the beginning, this directory has only one file, ``nr_goals``. Writing a
+number (``N``) to the file creates the number of child directories named ``0``
+to ``N-1``. Each directory represents each goal and current achievement.
+Among the multiple feedback, the best one is used.
+
+Each goal directory contains two files, namely ``target_value`` and
+``current_value``. Users can set and get any number to those files to set the
+feedback. User space main workload's latency or throughput, system metrics
+like free memory ratio or memory pressure stall time (PSI) could be example
+metrics for the values. Note that users should write
+``commit_schemes_quota_goals`` to the ``state`` file of the :ref:`kdamond
+directory <sysfs_kdamond>` to pass the feedback to DAMON.
+
schemes/<N>/watermarks/
-----------------------

diff --git a/Documentation/mm/damon/design.rst b/Documentation/mm/damon/design.rst
index 947c9df6cd33..8b4a49ac057d 100644
--- a/Documentation/mm/damon/design.rst
+++ b/Documentation/mm/damon/design.rst
@@ -346,6 +346,8 @@ the weight will be respected are up to the underlying prioritization mechanism
implementation.


+.. _damon_design_damos_quotas_auto_tuning:
+
Aim-oriented Feedback-driven Auto-tuning
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

--
2.34.1