diff options
Diffstat (limited to 'Documentation/admin-guide/mm/damon')
| -rw-r--r-- | Documentation/admin-guide/mm/damon/lru_sort.rst | 22 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/reclaim.rst | 22 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/stat.rst | 35 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/damon/usage.rst | 29 |
4 files changed, 91 insertions, 17 deletions
diff --git a/Documentation/admin-guide/mm/damon/lru_sort.rst b/Documentation/admin-guide/mm/damon/lru_sort.rst index 7b0775d281b4..72a943202676 100644 --- a/Documentation/admin-guide/mm/damon/lru_sort.rst +++ b/Documentation/admin-guide/mm/damon/lru_sort.rst @@ -211,6 +211,28 @@ End of target memory region in physical address. The end physical address of memory region that DAMON_LRU_SORT will do work against. By default, biggest System RAM is used as the region. +addr_unit +--------- + +A scale factor for memory addresses and bytes. + +This parameter is for setting and getting the :ref:`address unit +<damon_design_addr_unit>` parameter of the DAMON instance for DAMON_RECLAIM. + +``monitor_region_start`` and ``monitor_region_end`` should be provided in this +unit. For example, let's suppose ``addr_unit``, ``monitor_region_start`` and +``monitor_region_end`` are set as ``1024``, ``0`` and ``10``, respectively. +Then DAMON_LRU_SORT will work for 10 KiB length of physical address range that +starts from address zero (``[0 * 1024, 10 * 1024)`` in bytes). + +Stat parameters having ``bytes_`` prefix are also in this unit. For example, +let's suppose values of ``addr_unit``, ``bytes_lru_sort_tried_hot_regions`` and +``bytes_lru_sorted_hot_regions`` are ``1024``, ``42``, and ``32``, +respectively. Then it means DAMON_LRU_SORT tried to LRU-sort 42 KiB of hot +memory and successfully LRU-sorted 32 KiB of the memory in total. + +If unsure, use only the default value (``1``) and forget about this. + kdamond_pid ----------- diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst index af05ae617018..8eba3da8dcee 100644 --- a/Documentation/admin-guide/mm/damon/reclaim.rst +++ b/Documentation/admin-guide/mm/damon/reclaim.rst @@ -232,6 +232,28 @@ The end physical address of memory region that DAMON_RECLAIM will do work against. That is, DAMON_RECLAIM will find cold memory regions in this region and reclaims. By default, biggest System RAM is used as the region. +addr_unit +--------- + +A scale factor for memory addresses and bytes. + +This parameter is for setting and getting the :ref:`address unit +<damon_design_addr_unit>` parameter of the DAMON instance for DAMON_RECLAIM. + +``monitor_region_start`` and ``monitor_region_end`` should be provided in this +unit. For example, let's suppose ``addr_unit``, ``monitor_region_start`` and +``monitor_region_end`` are set as ``1024``, ``0`` and ``10``, respectively. +Then DAMON_RECLAIM will work for 10 KiB length of physical address range that +starts from address zero (``[0 * 1024, 10 * 1024)`` in bytes). + +``bytes_reclaim_tried_regions`` and ``bytes_reclaimed_regions`` are also in +this unit. For example, let's suppose values of ``addr_unit``, +``bytes_reclaim_tried_regions`` and ``bytes_reclaimed_regions`` are ``1024``, +``42``, and ``32``, respectively. Then it means DAMON_RECLAIM tried to reclaim +42 KiB memory and successfully reclaimed 32 KiB memory in total. + +If unsure, use only the default value (``1``) and forget about this. + skip_anon --------- diff --git a/Documentation/admin-guide/mm/damon/stat.rst b/Documentation/admin-guide/mm/damon/stat.rst index 4c517c2c219a..e5a5a2c4f803 100644 --- a/Documentation/admin-guide/mm/damon/stat.rst +++ b/Documentation/admin-guide/mm/damon/stat.rst @@ -10,6 +10,8 @@ on the system's entire physical memory using DAMON, and provides simplified access monitoring results statistics, namely idle time percentiles and estimated memory bandwidth. +.. _damon_stat_monitoring_accuracy_overhead: + Monitoring Accuracy and Overhead ================================ @@ -17,9 +19,11 @@ DAMON_STAT uses monitoring intervals :ref:`auto-tuning <damon_design_monitoring_intervals_autotuning>` to make its accuracy high and overhead minimum. It auto-tunes the intervals aiming 4 % of observable access events to be captured in each snapshot, while limiting the resulting sampling -events to be 5 milliseconds in minimum and 10 seconds in maximum. On a few +interval to be 5 milliseconds in minimum and 10 seconds in maximum. On a few production server systems, it resulted in consuming only 0.x % single CPU time, -while capturing reasonable quality of access patterns. +while capturing reasonable quality of access patterns. The tuning-resulting +intervals can be retrieved via ``aggr_interval_us`` :ref:`parameter +<damon_stat_aggr_interval_us>`. Interface: Module Parameters ============================ @@ -41,6 +45,18 @@ You can enable DAMON_STAT by setting the value of this parameter as ``Y``. Setting it as ``N`` disables DAMON_STAT. The default value is set by ``CONFIG_DAMON_STAT_ENABLED_DEFAULT`` build config option. +.. _damon_stat_aggr_interval_us: + +aggr_interval_us +---------------- + +Auto-tuned aggregation time interval in microseconds. + +Users can read the aggregation interval of DAMON that is being used by the +DAMON instance for DAMON_STAT. It is :ref:`auto-tuned +<damon_stat_monitoring_accuracy_overhead>` and therefore the value is +dynamically changed. + estimated_memory_bandwidth -------------------------- @@ -58,12 +74,13 @@ memory_idle_ms_percentiles Per-byte idle time (milliseconds) percentiles of the system. DAMON_STAT calculates how long each byte of the memory was not accessed until -now (idle time), based on the current DAMON results snapshot. If DAMON found a -region of access frequency (nr_accesses) larger than zero, every byte of the -region gets zero idle time. If a region has zero access frequency -(nr_accesses), how long the region was keeping the zero access frequency (age) -becomes the idle time of every byte of the region. Then, DAMON_STAT exposes -the percentiles of the idle time values via this read-only parameter. Reading -the parameter returns 101 idle time values in milliseconds, separated by comma. +now (idle time), based on the current DAMON results snapshot. For regions +having access frequency (nr_accesses) larger than zero, how long the current +access frequency level was kept multiplied by ``-1`` becomes the idlee time of +every byte of the region. If a region has zero access frequency (nr_accesses), +how long the region was keeping the zero access frequency (age) becomes the +idle time of every byte of the region. Then, DAMON_STAT exposes the +percentiles of the idle time values via this read-only parameter. Reading the +parameter returns 101 idle time values in milliseconds, separated by comma. Each value represents 0-th, 1st, 2nd, 3rd, ..., 99th and 100th percentile idle times. diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index eae534bc1bee..9991dad60fcf 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -67,7 +67,7 @@ comma (","). │ │ │ │ │ │ │ intervals_goal/access_bp,aggrs,min_sample_us,max_sample_us │ │ │ │ │ │ nr_regions/min,max │ │ │ │ │ :ref:`targets <sysfs_targets>`/nr_targets - │ │ │ │ │ │ :ref:`0 <sysfs_target>`/pid_target + │ │ │ │ │ │ :ref:`0 <sysfs_target>`/pid_target,obsolete_target │ │ │ │ │ │ │ :ref:`regions <sysfs_regions>`/nr_regions │ │ │ │ │ │ │ │ :ref:`0 <sysfs_region>`/start,end │ │ │ │ │ │ │ │ ... @@ -81,7 +81,7 @@ comma (","). │ │ │ │ │ │ │ :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_metric,target_value,current_value,nid + │ │ │ │ │ │ │ │ │ 0/target_metric,target_value,current_value,nid,path │ │ │ │ │ │ │ :ref:`watermarks <sysfs_watermarks>`/metric,interval_us,high,mid,low │ │ │ │ │ │ │ :ref:`{core_,ops_,}filters <sysfs_filters>`/nr_filters │ │ │ │ │ │ │ │ 0/type,matching,allow,memcg_path,addr_start,addr_end,target_idx,min,max @@ -134,7 +134,8 @@ Users can write below commands for the kdamond to the ``state`` file. - ``on``: Start running. - ``off``: Stop running. - ``commit``: Read the user inputs in the sysfs files except ``state`` file - again. + again. Monitoring :ref:`target region <sysfs_regions>` inputs are also be + ignored if no target region is specified. - ``update_tuned_intervals``: Update the contents of ``sample_us`` and ``aggr_us`` files of the kdamond with the auto-tuning applied ``sampling interval`` and ``aggregation interval`` for the files. Please refer to @@ -264,13 +265,20 @@ to ``N-1``. Each directory represents each monitoring target. targets/<N>/ ------------ -In each target directory, one file (``pid_target``) and one directory -(``regions``) exist. +In each target directory, two files (``pid_target`` and ``obsolete_target``) +and one directory (``regions``) exist. If you wrote ``vaddr`` to the ``contexts/<N>/operations``, each target should be a process. You can specify the process to DAMON by writing the pid of the process to the ``pid_target`` file. +Users can selectively remove targets in the middle of the targets array by +writing non-zero value to ``obsolete_target`` file and committing it (writing +``commit`` to ``state`` file). DAMON will remove the matching targets from its +internal targets array. Users are responsible to construct target directories +again, so that those correctly represent the changed internal targets array. + + .. _sysfs_regions: targets/<N>/regions @@ -289,6 +297,11 @@ In the beginning, this directory has only one file, ``nr_regions``. Writing a number (``N``) to the file creates the number of child directories named ``0`` to ``N-1``. Each directory represents each initial monitoring target region. +If ``nr_regions`` is zero when committing new DAMON parameters online (writing +``commit`` to ``state`` file of :ref:`kdamond <sysfs_kdamond>`), the commit +logic ignores the target regions. In other words, the current monitoring +results for the target are preserved. + .. _sysfs_region: regions/<N>/ @@ -402,9 +415,9 @@ 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 four files, namely ``target_metric``, -``target_value``, ``current_value`` and ``nid``. Users can set and get the -four parameters for the quota auto-tuning goals that specified on the +Each goal directory contains five files, namely ``target_metric``, +``target_value``, ``current_value`` ``nid`` and ``path``. Users can set and +get the five 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 |