From: SeongJae Park <sj@xxxxxxxxxx> Subject: Docs/admin-guide/mm/damon: document 'init_regions' feature This commit adds description of the 'init_regions' feature in the DAMON usage document. Link: https://lkml.kernel.org/r/20211012205711.29216-4-sj@xxxxxxxxxx Signed-off-by: SeongJae Park <sj@xxxxxxxxxx> Cc: Amit Shah <amit@xxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: David Rienjes <rientjes@xxxxxxxxxx> Cc: David Woodhouse <dwmw@xxxxxxxxxx> Cc: Greg Thelen <gthelen@xxxxxxxxxx> Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Leonard Foerster <foersleo@xxxxxxxxx> Cc: Marco Elver <elver@xxxxxxxxxx> Cc: Markus Boehme <markubo@xxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/admin-guide/mm/damon/usage.rst | 41 ++++++++++++++++- 1 file changed, 39 insertions(+), 2 deletions(-) --- a/Documentation/admin-guide/mm/damon/usage.rst~docs-admin-guide-mm-damon-document-init_regions-feature +++ a/Documentation/admin-guide/mm/damon/usage.rst @@ -34,8 +34,9 @@ the reason, this document describes only 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 ------- _
