This commit adds description of the 'init_regions' feature in the DAMON usage document. Signed-off-by: SeongJae Park <sj@xxxxxxxxxx> --- Documentation/admin-guide/mm/damon/usage.rst | 41 +++++++++++++++++++- 1 file changed, 39 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index c0296c14babf..f7d5cfbb50c2 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -34,8 +34,9 @@ the reason, this document describes only the debugfs interface debugfs Interface ================= -DAMON exports four files, ``attrs``, ``target_ids``, ``schemes`` and -``monitor_on`` under its debugfs directory, ``<debugfs>/damon/``. +DAMON exports five files, ``attrs``, ``target_ids``, ``init_regions``, +``schemes`` and ``monitor_on`` under its debugfs directory, +``<debugfs>/damon/``. Attributes @@ -74,6 +75,42 @@ check it again:: Note that setting the target ids doesn't start the monitoring. +Initial Monitoring Target Regions +--------------------------------- + +In case of the debugfs based monitoring, DAMON automatically sets and updates +the monitoring target regions so that entire memory mappings of target +processes can be covered. However, users can want to limit the monitoring +region to specific address ranges, such as the heap, the stack, or specific +file-mapped area. Or, some users can know the initial access pattern of their +workloads and therefore want to set optimal initial regions for the 'adaptive +regions adjustment'. + +In such cases, users can explicitly set the initial monitoring target regions +as they want, by writing proper values to the ``init_regions`` file. Each line +of the input should represent one region in below form.:: + + <target id> <start address> <end address> + +The ``target id`` should already in ``target_ids`` file, and the regions should +be passed in address order. For example, below commands will set a couple of +address ranges, ``1-100`` and ``100-200`` as the initial monitoring target +region of process 42, and another couple of address ranges, ``20-40`` and +``50-100`` as that of process 4242.:: + + # cd <debugfs>/damon + # echo "42 1 100 + 42 100 200 + 4242 20 40 + 4242 50 100" > init_regions + +Note that this sets the initial monitoring target regions only. In case of +virtual memory monitoring, DAMON will automatically updates the boundary of the +regions after one ``regions update interval``. Therefore, users should set the +``regions update interval`` large enough in this case, if they don't want the +update. + + Schemes ------- -- 2.17.1
