linux-kernel - [PATCH 7/8] Docs/admin-guide/mm/damon/stat: document aggr_interval

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Message-ID: <20251026182216.118200-8-sj@kernel.org>
Date: Sun, 26 Oct 2025 11:22:12 -0700
From: SeongJae Park <sj@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: SeongJae Park <sj@...nel.org>,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	David Hildenbrand <david@...hat.com>,
	Jonathan Corbet <corbet@....net>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	Michal Hocko <mhocko@...e.com>,
	Mike Rapoport <rppt@...nel.org>,
	Suren Baghdasaryan <surenb@...gle.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	damon@...ts.linux.dev,
	linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH 7/8] Docs/admin-guide/mm/damon/stat: document aggr_interval_us parameter

Commit cc7ceb1d14b0 ("mm/damon/stat: expose the current tuned
aggregation interval"), has introduced 'aggr_interval_us' parameter for
DAMON_STAT.  But the new parameter is not yet documented.  Document it
on the usage document for the module.

Signed-off-by: SeongJae Park <sj@...nel.org>
---
 Documentation/admin-guide/mm/damon/stat.rst | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/mm/damon/stat.rst b/Documentation/admin-guide/mm/damon/stat.rst
index 20f540a9d3d2..754f98d47617 100644
--- a/Documentation/admin-guide/mm/damon/stat.rst
+++ b/Documentation/admin-guide/mm/damon/stat.rst
@@ -10,6 +10,8 @@ on the system's entire physical memory using DAMON, and provides simplified
 access monitoring results statistics, namely idle time percentiles and
 estimated memory bandwidth.
 
+.. _damon_stat_monitoring_accuracy_overhead:
+
 Monitoring Accuracy and Overhead
 ================================
 
@@ -19,7 +21,9 @@ overhead minimum.  It auto-tunes the intervals aiming 4 % of observable access
 events to be captured in each snapshot, while limiting the resulting sampling
 interval to be 5 milliseconds in minimum and 10 seconds in maximum.  On a few
 production server systems, it resulted in consuming only 0.x % single CPU time,
-while capturing reasonable quality of access patterns.
+while capturing reasonable quality of access patterns.  The tuning-resulting
+intervals can be retrieved via ``aggr_interval_us`` :ref:`parameter
+<damon_stat_aggr_interval_us>`.
 
 Interface: Module Parameters
 ============================
@@ -41,6 +45,18 @@ 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.
 
+.. _damon_stat_aggr_interval_us:
+
+aggr_interval_us
+----------------
+
+Auto-tuned aggregation time interval in microseconds.
+
+Users can read the aggregation interval of DAMON that is being used by the
+DAMON instance for DAMON_STAT.  It is :ref:`auto-tuned
+<damon_stat_monitoring_accuracy_overhead>` and therefore the value is
+dynamically changed.
+
 estimated_memory_bandwidth
 --------------------------
 
-- 
2.47.3