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Docs/admin-guide/mm/damon/usage: document for quota goals

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

Link: https://lkml.kernel.org/r/20231130023652.50284-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
SeongJae Park 2023-11-30 02:36:52 +00:00 committed by Andrew Morton
parent 0972913f96
commit 6140edeea8
2 changed files with 43 additions and 7 deletions
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48
Documentation/admin-guide/mm/damon/usage.rst
View File

@ -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/
-----------------------

2
Documentation/mm/damon/design.rst
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@ -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
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^