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authorLiew Rui Yan <aethernet65535@gmail.com>2026-03-15 09:29:44 -0700
committerAndrew Morton <akpm@linux-foundation.org>2026-04-05 13:53:30 -0700
commit4bdbddb4e482f283b60787b97fc06b3da3fb419c (patch)
treebfdaf5bb30b78022166d70e22ab638cf05831459 /Documentation/admin-guide
parentbf989ade270d4ca65e73d5fc1ab5e4d2ef472e80 (diff)
Docs/mm/damon: document exclusivity of special-purpose modules
Add a section in design.rst to explain that DAMON special-purpose kernel modules (LRU_SORT, RECLAIM, STAT) run in an exclusive manner and return -EBUSY if another is already running. Update lru_sort.rst, reclaim.rst and stat.rst by adding cross-references to this exclusivity rule at the end of their respective Example sections. This change is motivated from another discussion [1]. Link: https://lkml.kernel.org/r/20260315162945.80994-1-sj@kernel.org Link: https://lore.kernel.org/damon/20260314002119.79742-1-sj@kernel.org/T/#t [1] Signed-off-by: Liew Rui Yan <aethernet65535@gmail.com> Reviewed-by: SeongJae Park <sj@kernel.org> Signed-off-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/mm/damon/lru_sort.rst5
-rw-r--r--Documentation/admin-guide/mm/damon/reclaim.rst5
-rw-r--r--Documentation/admin-guide/mm/damon/stat.rst5
3 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/admin-guide/mm/damon/lru_sort.rst b/Documentation/admin-guide/mm/damon/lru_sort.rst
index 73980bacc3a0..56690646cf39 100644
--- a/Documentation/admin-guide/mm/damon/lru_sort.rst
+++ b/Documentation/admin-guide/mm/damon/lru_sort.rst
@@ -351,3 +351,8 @@ the LRU-list based page granularity reclamation. ::
# echo 400 > wmarks_mid
# echo 200 > wmarks_low
# echo Y > enabled
+
+Note that this module (damon_lru_sort) cannot run simultaneously with other
+DAMON-based special-purpose modules. Refer to :ref:`DAMON design special
+purpose modules exclusivity <damon_design_special_purpose_modules_exclusivity>`
+for more details.
diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst
index 8eba3da8dcee..442ac5c64795 100644
--- a/Documentation/admin-guide/mm/damon/reclaim.rst
+++ b/Documentation/admin-guide/mm/damon/reclaim.rst
@@ -318,6 +318,11 @@ granularity reclamation. ::
# echo 200 > wmarks_low
# echo Y > enabled
+Note that this module (damon_reclaim) cannot run simultaneously with other
+DAMON-based special-purpose modules. Refer to :ref:`DAMON design special
+purpose modules exclusivity <damon_design_special_purpose_modules_exclusivity>`
+for more details.
+
.. [1] https://research.google/pubs/pub48551/
.. [2] https://lwn.net/Articles/787611/
.. [3] https://www.kernel.org/doc/html/latest/mm/free_page_reporting.html
diff --git a/Documentation/admin-guide/mm/damon/stat.rst b/Documentation/admin-guide/mm/damon/stat.rst
index e5a5a2c4f803..c4b14daeb2dd 100644
--- a/Documentation/admin-guide/mm/damon/stat.rst
+++ b/Documentation/admin-guide/mm/damon/stat.rst
@@ -45,6 +45,11 @@ You can enable DAMON_STAT by setting the value of this parameter as ``Y``.
Setting it as ``N`` disables DAMON_STAT. The default value is set by
``CONFIG_DAMON_STAT_ENABLED_DEFAULT`` build config option.
+Note that this module (damon_stat) cannot run simultaneously with other
+DAMON-based special-purpose modules. Refer to :ref:`DAMON design special
+purpose modules exclusivity <damon_design_special_purpose_modules_exclusivity>`
+for more details.
+
.. _damon_stat_aggr_interval_us:
aggr_interval_us