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-rw-r--r--Documentation/admin-guide/mm/damon/usage.rst158
1 files changed, 74 insertions, 84 deletions
diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst
index 87fdc258d1..7daf1a95f9 100644
--- a/Documentation/admin-guide/mm/damon/usage.rst
+++ b/Documentation/admin-guide/mm/damon/usage.rst
@@ -83,10 +83,10 @@ 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
+ │ │ │ │ │ │ │ │ │ 0/target_metric,target_value,current_value
│ │ │ │ │ │ │ :ref:`watermarks <sysfs_watermarks>`/metric,interval_us,high,mid,low
│ │ │ │ │ │ │ :ref:`filters <sysfs_filters>`/nr_filters
│ │ │ │ │ │ │ │ 0/type,matching,memcg_id
@@ -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_quotas``: 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.
@@ -180,19 +183,14 @@ In each context directory, two files (``avail_operations`` and ``operations``)
and three directories (``monitoring_attrs``, ``targets``, and ``schemes``)
exist.
-DAMON supports multiple types of monitoring operations, including those for
-virtual address space and the physical address space. You can get the list of
-available monitoring operations set on the currently running kernel by reading
+DAMON supports multiple types of :ref:`monitoring operations
+<damon_design_configurable_operations_set>`, including those for virtual address
+space and the physical address space. You can get the list of available
+monitoring operations set on the currently running kernel by reading
``avail_operations`` file. Based on the kernel configuration, the file will
-list some or all of below keywords.
-
- - vaddr: Monitor virtual address spaces of specific processes
- - fvaddr: Monitor fixed virtual address ranges
- - paddr: Monitor the physical address space of the system
-
-Please refer to :ref:`regions sysfs directory <sysfs_regions>` for detailed
-differences between the operations sets in terms of the monitoring target
-regions.
+list different available operation sets. Please refer to the :ref:`design
+<damon_operations_set>` for the list of all available operation sets and their
+brief explanations.
You can set and get what type of monitoring operations DAMON will use for the
context by writing one of the keywords listed in ``avail_operations`` file and
@@ -247,17 +245,11 @@ process to the ``pid_target`` file.
targets/<N>/regions
-------------------
-When ``vaddr`` monitoring operations set is being used (``vaddr`` is written to
-the ``contexts/<N>/operations`` file), DAMON automatically sets and updates the
-monitoring target regions so that entire memory mappings of target processes
-can be covered. However, users could want to set the initial monitoring region
-to specific address ranges.
-
-In contrast, DAMON do not automatically sets and updates the monitoring target
-regions when ``fvaddr`` or ``paddr`` monitoring operations sets are being used
-(``fvaddr`` or ``paddr`` have written to the ``contexts/<N>/operations``).
-Therefore, users should set the monitoring target regions by themselves in the
-cases.
+In case of ``fvaddr`` or ``paddr`` monitoring operations sets, users are
+required to set the monitoring target address ranges. In case of ``vaddr``
+operations set, it is not mandatory, but users can optionally set the initial
+monitoring region to specific address ranges. Please refer to the :ref:`design
+<damon_design_vaddr_target_regions_construction>` for more details.
For such cases, users can explicitly set the initial monitoring target regions
as they want, by writing proper values to the files under this directory.
@@ -302,27 +294,8 @@ In each scheme directory, five directories (``access_pattern``, ``quotas``,
The ``action`` file is for setting and getting the scheme's :ref:`action
<damon_design_damos_action>`. The keywords that can be written to and read
-from the file and their meaning are as below.
-
-Note that support of each action depends on the running DAMON operations set
-:ref:`implementation <sysfs_context>`.
-
- - ``willneed``: Call ``madvise()`` for the region with ``MADV_WILLNEED``.
- Supported by ``vaddr`` and ``fvaddr`` operations set.
- - ``cold``: Call ``madvise()`` for the region with ``MADV_COLD``.
- Supported by ``vaddr`` and ``fvaddr`` operations set.
- - ``pageout``: Call ``madvise()`` for the region with ``MADV_PAGEOUT``.
- Supported by ``vaddr``, ``fvaddr`` and ``paddr`` operations set.
- - ``hugepage``: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``.
- Supported by ``vaddr`` and ``fvaddr`` operations set.
- - ``nohugepage``: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``.
- Supported by ``vaddr`` and ``fvaddr`` operations set.
- - ``lru_prio``: Prioritize the region on its LRU lists.
- Supported by ``paddr`` operations set.
- - ``lru_deprio``: Deprioritize the region on its LRU lists.
- Supported by ``paddr`` operations set.
- - ``stat``: Do nothing but count the statistics.
- Supported by all operations sets.
+from the file and their meaning are same to those of the list on
+:ref:`design doc <damon_design_damos_action>`.
The ``apply_interval_us`` file is for setting and getting the scheme's
:ref:`apply_interval <damon_design_damos>` in microseconds.
@@ -350,8 +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,
@@ -359,7 +333,17 @@ respectively. Then, DAMON tries to use only up to ``time quota`` milliseconds
for applying the ``action`` to memory regions of the ``access_pattern``, and to
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.
+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_quotas`` to
+the relevant ``kdamonds/<N>/state`` file.
Under ``weights`` directory, three files (``sz_permil``,
``nr_accesses_permil``, and ``age_permil``) exist.
@@ -382,11 +366,11 @@ 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
+Each goal directory contains three files, namely ``target_metric``,
+``target_value`` and ``current_value``. Users can set and get the three
+parameters for the quota auto-tuning goals that specified on the :ref:`design
+doc <damon_design_damos_quotas_auto_tuning>` by writing to and reading from each
+of the files. Note that users should further write
``commit_schemes_quota_goals`` to the ``state`` file of the :ref:`kdamond
directory <sysfs_kdamond>` to pass the feedback to DAMON.
@@ -579,11 +563,11 @@ monitoring results recording.
While the monitoring is turned on, you could record the tracepoint events and
show results using tracepoint supporting tools like ``perf``. For example::
- # echo on > monitor_on
+ # echo on > kdamonds/0/state
# perf record -e damon:damon_aggregated &
# sleep 5
# kill 9 $(pidof perf)
- # echo off > monitor_on
+ # echo off > kdamonds/0/state
# perf script
kdamond.0 46568 [027] 79357.842179: damon:damon_aggregated: target_id=0 nr_regions=11 122509119488-135708762112: 0 864
[...]
@@ -628,9 +612,17 @@ debugfs Interface (DEPRECATED!)
move, please report your usecase to damon@lists.linux.dev and
linux-mm@kvack.org.
-DAMON exports eight files, ``attrs``, ``target_ids``, ``init_regions``,
-``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts`` and
-``rm_contexts`` under its debugfs directory, ``<debugfs>/damon/``.
+DAMON exports nine files, ``DEPRECATED``, ``attrs``, ``target_ids``,
+``init_regions``, ``schemes``, ``monitor_on_DEPRECATED``, ``kdamond_pid``,
+``mk_contexts`` and ``rm_contexts`` under its debugfs directory,
+``<debugfs>/damon/``.
+
+
+``DEPRECATED`` is a read-only file for the DAMON debugfs interface deprecation
+notice. Reading it returns the deprecation notice, as below::
+
+ # cat DEPRECATED
+ DAMON debugfs interface is deprecated, so users should move to DAMON_SYSFS. If you cannot, please report your usecase to damon@lists.linux.dev and linux-mm@kvack.org.
Attributes
@@ -755,19 +747,17 @@ Action
~~~~~~
The ``<action>`` is a predefined integer for memory management :ref:`actions
-<damon_design_damos_action>`. The supported numbers and their meanings are as
-below.
-
- - 0: Call ``madvise()`` for the region with ``MADV_WILLNEED``. Ignored if
- ``target`` is ``paddr``.
- - 1: Call ``madvise()`` for the region with ``MADV_COLD``. Ignored if
- ``target`` is ``paddr``.
- - 2: Call ``madvise()`` for the region with ``MADV_PAGEOUT``.
- - 3: Call ``madvise()`` for the region with ``MADV_HUGEPAGE``. Ignored if
- ``target`` is ``paddr``.
- - 4: Call ``madvise()`` for the region with ``MADV_NOHUGEPAGE``. Ignored if
- ``target`` is ``paddr``.
- - 5: Do nothing but count the statistics
+<damon_design_damos_action>`. The mapping between the ``<action>`` values and
+the memory management actions is as below. For the detailed meaning of the
+action and DAMON operations set supporting each action, please refer to the
+list on :ref:`design doc <damon_design_damos_action>`.
+
+ - 0: ``willneed``
+ - 1: ``cold``
+ - 2: ``pageout``
+ - 3: ``hugepage``
+ - 4: ``nohugepage``
+ - 5: ``stat``
Quota
~~~~~
@@ -848,16 +838,16 @@ Turning On/Off
Setting the files as described above doesn't incur effect unless you explicitly
start the monitoring. You can start, stop, and check the current status of the
-monitoring by writing to and reading from the ``monitor_on`` file. Writing
-``on`` to the file starts the monitoring of the targets with the attributes.
-Writing ``off`` to the file stops those. DAMON also stops if every target
-process is terminated. Below example commands turn on, off, and check the
-status of DAMON::
+monitoring by writing to and reading from the ``monitor_on_DEPRECATED`` file.
+Writing ``on`` to the file starts the monitoring of the targets with the
+attributes. Writing ``off`` to the file stops those. DAMON also stops if
+every target process is terminated. Below example commands turn on, off, and
+check the status of DAMON::
# cd <debugfs>/damon
- # echo on > monitor_on
- # echo off > monitor_on
- # cat monitor_on
+ # echo on > monitor_on_DEPRECATED
+ # echo off > monitor_on_DEPRECATED
+ # cat monitor_on_DEPRECATED
off
Please note that you cannot write to the above-mentioned debugfs files while
@@ -873,11 +863,11 @@ can get the pid of the thread by reading the ``kdamond_pid`` file. When the
monitoring is turned off, reading the file returns ``none``. ::
# cd <debugfs>/damon
- # cat monitor_on
+ # cat monitor_on_DEPRECATED
off
# cat kdamond_pid
none
- # echo on > monitor_on
+ # echo on > monitor_on_DEPRECATED
# cat kdamond_pid
18594
@@ -907,5 +897,5 @@ directory by putting the name of the context to the ``rm_contexts`` file. ::
# ls foo
# ls: cannot access 'foo': No such file or directory
-Note that ``mk_contexts``, ``rm_contexts``, and ``monitor_on`` files are in the
-root directory only.
+Note that ``mk_contexts``, ``rm_contexts``, and ``monitor_on_DEPRECATED`` files
+are in the root directory only.