mm/damon/usage.rst

159 ``contexts`` directory contains files for controlling the monitoring contexts
169 ``0`` to ``N-1``.  Each directory represents each monitoring context (refer to
183 DAMON supports multiple types of monitoring operations, including those for
185 available monitoring operations set on the currently running kernel by reading
194 differences between the operations sets in terms of the monitoring target
197 You can set and get what type of monitoring operations DAMON will use for the
206 Files for specifying attributes of the monitoring including required quality
207 and efficiency of the monitoring are in ``monitoring_attrs`` directory.
217 of DAMON's monitoring regions (``min`` and ``max``, respectively), which
218 controls the monitoring overhead, exist.  You can set and get the values by
221 For more details about the intervals and monitoring regions range, please refer
231 to ``N-1``.  Each directory represents each monitoring target.
250 When ``vaddr`` monitoring operations set is being used (``vaddr`` is written to
252 monitoring target regions so that entire memory mappings of target processes
253 can be covered.  However, users could want to set the initial monitoring region
256 In contrast, DAMON do not automatically sets and updates the monitoring target
257 regions when ``fvaddr`` or ``paddr`` monitoring operations sets are being used
259 Therefore, users should set the monitoring target regions by themselves in the
262 For such cases, users can explicitly set the initial monitoring target regions
267 to ``N-1``.  Each directory represents each initial monitoring target region.
275 can set and get the start and end addresses of the initial monitoring target
431 open-ended interval), or ``target`` for specific DAMON monitoring target
436 ``addr_start`` and ``addr_end`` files, respectively.  For the DAMON monitoring
438 the DAMON context's monitoring targets list to ``target_idx`` file.  You can
507 and query-like efficient data access monitoring results retrievals.  For the
529 free memory rate of the system every 5 seconds, start the monitoring and paging
563 Tracepoints for Monitoring Results
566 Users can get the monitoring results via the :ref:`tried_regions
568 snapshot, but it could be inefficient for fully recording all the monitoring
571 provides the whole monitoring results, while ``damon:damos_before_apply``
572 provides the monitoring results for regions that each DAMON-based Operation
577 monitoring results recording.
579 While the monitoring is turned on, you could record the tracepoint events and
591 Each line of the perf script output represents each monitoring region.  The
593 (``target_id=X``) shows the ide of the monitoring target of the region.  The
594 seventh field (``nr_regions=X``) shows the total number of monitoring regions
609 Each line of the output represents each monitoring region that each DAMON-based
640 ``update interval``, and min/max number of monitoring target regions by
641 reading from and writing to the ``attrs`` file.  To know about the monitoring
655 Some types of address spaces supports multiple monitoring target.  For example,
656 the virtual memory address spaces monitoring can have multiple processes as the
657 monitoring targets.  Users can set the targets by writing relevant id values of
659 ``target_ids`` file.  In case of the virtual address spaces monitoring, the
660 values should be pids of the monitoring target processes.  For example, below
661 commands set processes having pids 42 and 4242 as the monitoring targets and
671 space monitoring doesn't support multiple targets, reading the file will show a
679 Note that setting the target ids doesn't start the monitoring.
682 Initial Monitoring Target Regions
685 In case of the virtual address space monitoring, DAMON automatically sets and
686 updates the monitoring target regions so that entire memory mappings of target
687 processes can be covered.  However, users can want to limit the monitoring
693 In contrast, DAMON do not automatically sets and updates the monitoring target
694 regions in case of physical memory monitoring.  Therefore, users should set the
695 monitoring target regions by themselves.
697 In such cases, users can explicitly set the initial monitoring target regions
707 ``100-200`` as the initial monitoring target region of pid 42, which is the
720 Note that this sets the initial monitoring target regions only.  In case of
721 virtual memory monitoring, DAMON will automatically updates the boundary of the
834 free memory rate of the system every 5 seconds, start the monitoring and paging
850 start the monitoring.  You can start, stop, and check the current status of the
851 monitoring by writing to and reading from the ``monitor_on`` file.  Writing
852 ``on`` to the file starts the monitoring of the targets with the attributes.
864 the monitoring is turned on.  If you write to the files while DAMON is running,
868 Monitoring Thread PID
871 DAMON does requested monitoring with a kernel thread called ``kdamond``.  You
873 monitoring is turned off, reading the file returns ``none``. ::
885 Using Multiple Monitoring Threads
888 One ``kdamond`` thread is created for each monitoring context.  You can create
889 and remove monitoring contexts for multiple ``kdamond`` required use case using