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docs-mm-damon-document-exclusivity-of-special-purpose-modules.patch removed from -mm tree

merged mm-stable Andrew Morton 1 participant 1 message Mar 29

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The quilt patch titled
Subject: Docs/mm/damon: document exclusivity of special-purpose modules
has been removed from the -mm tree. Its filename was
docs-mm-damon-document-exclusivity-of-special-purpose-modules.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: Liew Rui Yan <[email protected]>
Subject: Docs/mm/damon: document exclusivity of special-purpose modules
Date: Sun, 15 Mar 2026 09:29:44 -0700

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/[email protected] open here
Link https://lore.kernel.org/damon/[email protected]/T/#t [1] open here
Signed-off-by Liew Rui Yan <[email protected]>
Reviewed-by SeongJae Park <[email protected]>
Signed-off-by SeongJae Park <[email protected]>
Cc David Hildenbrand <[email protected]>
Cc Jonathan Corbet <[email protected]>
Cc Liam Howlett <[email protected]>
Cc Lorenzo Stoakes (Oracle) <[email protected]>
Cc Michal Hocko <[email protected]>
Cc Mike Rapoport <[email protected]>
Cc Shuah Khan <[email protected]>
Cc Suren Baghdasaryan <[email protected]>
Cc Vlastimil Babka <[email protected]>
Signed-off-by Andrew Morton <[email protected]>

---

 Documentation/admin-guide/mm/damon/lru_sort.rst |    5 +++++
 Documentation/admin-guide/mm/damon/reclaim.rst  |    5 +++++
 Documentation/admin-guide/mm/damon/stat.rst     |    5 +++++
 Documentation/mm/damon/design.rst               |    4 ++++
 4 files changed, 19 insertions(+)
Documentation/admin-guide/mm/damon/lru_sort.rst renamed from Documentation/admin-guide/mm/damon/lru_sort.rst~docs-mm-damon-document-exclusivity-of-special-purpose-modules +5 -0
@@ -351,3 +351,8 @@ the LRU-list based page granularity recl
     # 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.
Documentation/admin-guide/mm/damon/reclaim.rst renamed from Documentation/admin-guide/mm/damon/reclaim.rst~docs-mm-damon-document-exclusivity-of-special-purpose-modules +5 -0
@@ -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
Documentation/admin-guide/mm/damon/stat.rst renamed from Documentation/admin-guide/mm/damon/stat.rst~docs-mm-damon-document-exclusivity-of-special-purpose-modules +5 -0
@@ -45,6 +45,11 @@ You can enable DAMON_STAT by setting the
 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
Documentation/mm/damon/design.rst renamed from Documentation/mm/damon/design.rst~docs-mm-damon-document-exclusivity-of-special-purpose-modules +4 -0
@@ -853,6 +853,10 @@ more detail, please read the usage docum
 (:doc:`/admin-guide/mm/damon/stat`, :doc:`/admin-guide/mm/damon/reclaim` and
 :doc:`/admin-guide/mm/damon/lru_sort`).
 
+.. _damon_design_special_purpose_modules_exclusivity:
+
+Note that these modules currently run in an exclusive manner.  If one of those
+is already running, others will return ``-EBUSY`` upon start requests.
 
 Sample DAMON Modules
 --------------------

_

Patches currently in -mm which might be from [email protected] are