diff options
Diffstat (limited to 'Documentation/admin-guide/mm/damon')
| -rw-r--r-- | Documentation/admin-guide/mm/damon/reclaim.rst | 27 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/usage.rst | 158 |
2 files changed, 101 insertions, 84 deletions
diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst index 343e25b252..af05ae6170 100644 --- a/Documentation/admin-guide/mm/damon/reclaim.rst +++ b/Documentation/admin-guide/mm/damon/reclaim.rst @@ -117,6 +117,33 @@ milliseconds. 1 second by default. +quota_mem_pressure_us +--------------------- + +Desired level of memory pressure-stall time in microseconds. + +While keeping the caps that set by other quotas, DAMON_RECLAIM automatically +increases and decreases the effective level of the quota aiming this level of +memory pressure is incurred. System-wide ``some`` memory PSI in microseconds +per quota reset interval (``quota_reset_interval_ms``) is collected and +compared to this value to see if the aim is satisfied. Value zero means +disabling this auto-tuning feature. + +Disabled by default. + +quota_autotune_feedback +----------------------- + +User-specifiable feedback for auto-tuning of the effective quota. + +While keeping the caps that set by other quotas, DAMON_RECLAIM automatically +increases and decreases the effective level of the quota aiming receiving this +feedback of value ``10,000`` from the user. DAMON_RECLAIM assumes the feedback +value and the quota are positively proportional. Value zero means disabling +this auto-tuning feature. + +Disabled by default. + wmarks_interval --------------- 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. |