The patch titled
Subject: Docs/mm/damon/design: add 'statistics' section
has been added to the -mm mm-unstable branch. Its filename is
docs-mm-damon-design-add-statistics-section.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/docs-mm-damon-design-add-statistics-section.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
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
samples-add-a-skeleton-of-a-sample-damon-module-for-working-set-size-estimation.patch
samples-damon-wsse-start-and-stop-damon-as-the-user-requests.patch
samples-damon-wsse-implement-working-set-size-estimation-and-logging.patch
samples-damon-introduce-a-skeleton-of-a-smaple-damon-module-for-proactive-reclamation.patch
samples-damon-prcl-implement-schemes-setup.patch
replace-free-hugepage-folios-after-migration-fix-2.patch
docs-admin-guide-mm-damon-usage-remove-damon-debugfs-interface-documentation.patch
docs-mm-damon-design-update-for-removal-of-damon-debugfs-interface.patch
selftests-damon-config-remove-configs-for-damon-debugfs-interface-selftests.patch
selftests-damon-remove-tests-for-damon-debugfs-interface.patch
kunit-configs-remove-configs-for-damon-debugfs-interface-tests.patch
mm-damon-remove-damon-debugfs-interface-kunit-tests.patch
mm-damon-remove-damon-debugfs-interface.patch
mm-damon-sysfs-schemes-remove-unnecessary-schemes-existence-check-in-damon_sysfs_schemes_clear_regions.patch
mm-damon-sysfs-handle-clear_schemes_tried_regions-from-damon-sysfs-context.patch
mm-damon-core-introduce-damon_call.patch
mm-damon-sysfs-use-damon_call-for-update_schemes_stats.patch
mm-damon-sysfs-use-damon_call-for-commit_schemes_quota_goals.patch
mm-damon-sysfs-use-damon_call-for-update_schemes_effective_quotas.patch
mm-damon-core-implement-damos_walk.patch
docs-mm-damon-design-document-damos-regions-walking.patch
mm-damon-sysfs-use-damos_walk-for-update_schemes_tried_bytesregions.patch
mm-damon-sysfs-remove-unused-code-for-schemes-tried-regions-update.patch
mm-damon-clarify-trying-vs-applying-on-damos_stat-kernel-doc-comment.patch
docs-mm-damon-design-add-statistics-section.patch
docs-admin-guide-mm-damon-usage-link-damos-stat-design-doc.patch
mm-damon-ask-apply_scheme-to-report-filter-passed-region-internal-bytes.patch
mm-damon-paddr-report-filter-passed-bytes-back-for-normal-actions.patch
mm-damon-paddr-report-filter-passed-bytes-back-for-damos_stat-action.patch
mm-damon-core-implement-per-scheme-ops-handled-filter-passed-bytes-stat.patch
mm-damon-syfs-schemes-implement-per-scheme-filter-passed-bytes-stat.patch
docs-mm-damon-design-document-sz_ops_filter_passed.patch
docs-admin-guide-mm-damon-usage-document-sz_ops_filter_passed.patch
docs-abi-damon-document-per-scheme-filter-passed-bytes-stat-file.patch
mm-damon-core-pass-per-region-filter-passed-bytes-to-damos_walk_control-walk_fn.patch
mm-damon-sysfs-schemes-expose-per-region-filter-passed-bytes.patch
docs-mm-damon-design-document-per-region-sz_filter_passed-stat.patch
docs-admin-guide-mm-damon-usage-document-sz_filtered_out-of-scheme-tried-region-directories.patch
docs-abi-damon-document-per-region-damos-filter-passed-bytes-stat-file.patch
