Docs/admin-guide/mm/damon/usage: document effective_bytes file

Update DAMON usage document for the effective quota file of the DAMON
sysfs interface.

Link: https://lkml.kernel.org/r/20240219194431.159606-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
SeongJae Park 2024-02-19 11:44:16 -08:00 committed by Andrew Morton
parent 68c4905bba
commit a6068d6dfa

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@ -83,7 +83,7 @@ comma (",").
│ │ │ │ │ │ │ │ sz/min,max
│ │ │ │ │ │ │ │ nr_accesses/min,max
│ │ │ │ │ │ │ │ age/min,max
│ │ │ │ │ │ │ :ref:`quotas <sysfs_quotas>`/ms,bytes,reset_interval_ms
│ │ │ │ │ │ │ :ref:`quotas <sysfs_quotas>`/ms,bytes,reset_interval_ms,effective_bytes
│ │ │ │ │ │ │ │ weights/sz_permil,nr_accesses_permil,age_permil
│ │ │ │ │ │ │ │ :ref:`goals <sysfs_schemes_quota_goals>`/nr_goals
│ │ │ │ │ │ │ │ │ 0/target_value,current_value
@ -153,6 +153,9 @@ Users can write below commands for the kdamond to the ``state`` file.
- ``clear_schemes_tried_regions``: Clear the DAMON-based operating scheme
action tried regions directory for each DAMON-based operation scheme of the
kdamond.
- ``update_schemes_effective_bytes``: Update the contents of
``effective_bytes`` files for each DAMON-based operation scheme of the
kdamond. For more details, refer to :ref:`quotas directory <sysfs_quotas>`.
If the state is ``on``, reading ``pid`` shows the pid of the kdamond thread.
@ -320,8 +323,9 @@ schemes/<N>/quotas/
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 two directores (``weights`` and ``goals``) exist.
Under ``quotas`` directory, four files (``ms``, ``bytes``,
``reset_interval_ms``, ``effective_bytes``) 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,
@ -332,6 +336,15 @@ apply the action to only up to ``bytes`` bytes of memory regions within the
quota limits unless at least one :ref:`goal <sysfs_schemes_quota_goals>` is
set.
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
effective size quota is further adjusted. Reading ``effective_bytes`` returns
the current effective size quota. The file is not updated in real time, so
users should ask DAMON sysfs interface to update the content of the file for
the stats by writing a special keyword, ``update_schemes_effective_bytes`` to
the relevant ``kdamonds/<N>/state`` file.
Under ``weights`` directory, three files (``sz_permil``,
``nr_accesses_permil``, and ``age_permil``) exist.
You can set the :ref:`prioritization weights