+ docs-admin-guide-mm-damon-usage-document-empty-target-regions-commit-behavior.patch added to mm-unstable branch

+ docs-admin-guide-mm-damon-usage-document-empty-target-regions-commit-behavior.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: Docs/admin-guide/mm/damon/usage: document empty target regions commit behavior
has been added to the -mm mm-unstable branch.  Its filename is
     docs-admin-guide-mm-damon-usage-document-empty-target-regions-commit-behavior.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/docs-admin-guide-mm-damon-usage-document-empty-target-regions-commit-behavior.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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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

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------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: Docs/admin-guide/mm/damon/usage: document empty target regions commit behavior
Date: Sun, 26 Oct 2025 11:22:09 -0700

Committing a monitoring target with empty target regions is for keeping
the current monitoring results.  This behavior was introduced by commit
973233600676 ("mm/damon/sysfs: update monitoring target regions for online
input commit").  The behavior is not documented, though.  Update the usage
document for clarifying this behavior.

Link: https://lkml.kernel.org/r/20251026182216.118200-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/admin-guide/mm/damon/usage.rst |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/Documentation/admin-guide/mm/damon/usage.rst~docs-admin-guide-mm-damon-usage-document-empty-target-regions-commit-behavior
+++ a/Documentation/admin-guide/mm/damon/usage.rst
@@ -134,7 +134,8 @@ Users can write below commands for the k
 - ``on``: Start running.
 - ``off``: Stop running.
 - ``commit``: Read the user inputs in the sysfs files except ``state`` file
-  again.
+  again.  Monitoring :ref:`target region <sysfs_regions>` inputs are also be
+  ignored if no target region is specified.
 - ``update_tuned_intervals``: Update the contents of ``sample_us`` and
   ``aggr_us`` files of the kdamond with the auto-tuning applied ``sampling
   interval`` and ``aggregation interval`` for the files.  Please refer to
@@ -289,6 +290,11 @@ In the beginning, this directory has onl
 number (``N``) to the file creates the number of child directories named ``0``
 to ``N-1``.  Each directory represents each initial monitoring target region.
 
+If ``nr_regions`` is zero when committing new DAMON parameters online (writing
+``commit`` to ``state`` file of :ref:`kdamond <sysfs_kdamond>`), the commit
+logic ignores the target regions.  In other words, the current monitoring
+results for the target are preserved.
+
 .. _sysfs_region:
 
 regions/<N>/
_

Patches currently in -mm which might be from sj@kernel.org are

mm-zswap-remove-unnecessary-dlen-writes-for-incompressible-pages.patch
mm-zswap-fix-typos-s-zwap-zswap.patch
mm-zswap-s-red-black-tree-xarray.patch
docs-admin-guide-mm-zswap-s-red-black-tree-xarray.patch
mm-damon-document-damos_quota_goal-nid-use-case.patch
mm-damon-add-damos-quota-goal-type-for-per-memcg-per-node-memory-usage.patch
mm-damon-core-implement-damos_quota_node_memcg_used_bp.patch
mm-damon-sysfs-schemes-implement-path-file-under-quota-goal-directory.patch
mm-damon-sysfs-schemes-support-damos_quota_node_memcg_used_bp.patch
mm-damon-core-add-damos-quota-gaol-metric-for-per-memcg-per-numa-free-memory.patch
mm-damon-sysfs-schemes-support-damos_quota_node_memcg_free_bp.patch
docs-mm-damon-design-document-damos_quota_node_memcg_usedfree_bp.patch
docs-admin-guide-mm-damon-usage-document-damos-quota-goal-path-file.patch
docs-abi-damon-document-damos-quota-goal-path-file.patch
mm-damon-core-fix-wrong-comment-of-damon_call-return-timing.patch
docs-mm-damon-design-fix-wrong-link-to-intervals-goal-section.patch
docs-admin-guide-mm-damon-stat-fix-a-typo-s-sampling-events-sampling-interval.patch
docs-admin-guide-mm-damon-usage-document-empty-target-regions-commit-behavior.patch
docs-admin-guide-mm-damon-reclaim-document-addr_unit-parameter.patch
docs-admin-guide-mm-damon-lru_sort-document-addr_unit-parameter.patch
docs-admin-guide-mm-damon-stat-document-aggr_interval_us-parameter.patch
docs-admin-guide-mm-damon-stat-document-negative-idle-time.patch
mm-damon-core-add-damon_target-obsolete-for-pin-point-removal.patch
mm-damon-sysfs-test-commit-input-against-realistic-destination.patch
mm-damon-sysfs-implement-obsolete_target-file.patch
docs-admin-guide-mm-damon-usage-document-obsolete_target-file.patch
docs-abi-damon-document-obsolete_target-sysfs-file.patch
selftests-damon-_damon_sysfs-support-obsolete_target-file.patch
drgn_dump_damon_status-dump-damon_target-obsolete.patch
sysfspy-extend-assert_ctx_committed-for-monitoring-targets.patch
selftests-damon-sysfs-add-obsolete_target-test.patch