The quilt patch titled
Subject: Docs/mm/damon/design: add 'statistics' section
has been removed from the -mm tree. Its filename was
docs-mm-damon-design-add-statistics-section.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: SeongJae Park <sj@xxxxxxxxxx>
Subject: Docs/mm/damon/design: add 'statistics' section
Date: Mon, 6 Jan 2025 11:33:47 -0800
DAMOS stats are important feature for tuning of DAMOS-based access-aware
system operation, and efficient access pattern monitoring. But not well
documented on the design document. Add a section on the document.
Link: https://lkml.kernel.org/r/20250106193401.109161-3-sj@xxxxxxxxxx
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/mm/damon/design.rst | 38 ++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)
--- a/Documentation/mm/damon/design.rst~docs-mm-damon-design-add-statistics-section
+++ a/Documentation/mm/damon/design.rst
@@ -539,6 +539,44 @@ To know how user-space can set the water
<sysfs_interface>`, refer to :ref:`filters <sysfs_filters>` part of the
documentation.
+Statistics
+~~~~~~~~~~
+
+The statistics of DAMOS behaviors that designed to help monitoring, tuning and
+debugging of DAMOS.
+
+DAMOS accounts below statistics for each scheme, from the beginning of the
+scheme's execution.
+
+- ``nr_tried``: Total number of regions that the scheme is tried to be applied.
+- ``sz_trtied``: Total size of regions that the scheme is tried to be applied.
+- ``nr_applied``: Total number of regions that the scheme is applied.
+- ``sz_applied``: Total size of regions that the scheme is applied.
+- ``qt_exceeds``: Total number of times the quota of the scheme has exceeded.
+
+"A scheme is tried to be applied to a region" means DAMOS core logic determined
+the region is eligible to apply the scheme's :ref:`action
+<damon_design_damos_action>`. The :ref:`access pattern
+<damon_design_damos_access_pattern>`, :ref:`quotas
+<damon_design_damos_quotas>`, :ref:`watermarks
+<damon_design_damos_watermarks>`, and :ref:`filters
+<damon_design_damos_filters>` that handled on core logic could affect this.
+The core logic will only ask the underlying :ref:`operation set
+<damon_operations_set>` to do apply the action to the region, so whether the
+action is really applied or not is unclear. That's why it is called "tried".
+
+"A scheme is applied to a region" means the :ref:`operation set
+<damon_operations_set>` has applied the action to at least a part of the
+region. The :ref:`filters <damon_design_damos_filters>` that handled by the
+operation set, and the types of the :ref:`action <damon_design_damos_action>`
+and the pages of the region can affect this. For example, if a filter is set
+to exclude anonymous pages and the region has only anonymous pages, or if the
+action is ``pageout`` while all pages of the region are unreclaimable, applying
+the action to the region will fail.
+
+To know how user-space can read the stats via :ref:`DAMON sysfs interface
+<sysfs_interface>`, refer to :ref:s`stats <sysfs_stats>` part of the
+documentation.
Regions Walking
~~~~~~~~~~~~~~~
_
Patches currently in -mm which might be from sj@xxxxxxxxxx are
docs-mm-damon-design-add-monitoring-parameters-tuning-guide.patch
docs-mm-damon-add-an-example-monitoring-intervals-tuning.patch
docs-admin-guide-mm-damon-usage-fix-and-add-missing-damos-filter-sysfs-files-on-files-hierarchy.patch
docs-admin-guide-mm-damon-start-update-snapshot-example.patch
mm-damon-explain-effective-quota-on-kernel-doc-comment.patch
