[PATCH 4/4] mm/damon: document that a zero sample_interval is accepted

From: SJ Park

Date: Mon Sep 21 2026 - 11:25:37 EST


From: Karthikeyan KS <karthiproffesional@xxxxxxxxx>

damon_set_attrs() accepts sample_interval == 0. This was reported as a
bug in v1 of this patch (rejecting it in damon_set_attrs()). A similar
patch was already declined for the same reason: a zero interval is
intentionally supported [1].

Document the behavior instead of changing it.

[1] https://lore.kernel.org/all/20260722094304.3132750-1-dayou5941@xxxxxxx/

Signed-off-by: Karthikeyan KS <karthiproffesional@xxxxxxxxx>
Reviewed-by: SJ Park <sj@xxxxxxxxxx>
Signed-off-by: SJ Park <sj@xxxxxxxxxx>
---
Changes from v2
- v2: https://lore.kernel.org/20260918131301.75879-1-karthiproffesional@xxxxxxxxx
- Collect R-b: from SJ.
- Rebas to the latest mm-new.
Changes from v1:
- Dropped the damon_set_attrs() rejection and the KUnit cases that
tested it.
- Added a kernel-doc note on struct damon_attrs's @sample_interval
instead.

include/linux/damon.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 836353c4ab9a..844b175120f0 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -836,7 +836,8 @@ struct damon_probe {
/**
* struct damon_attrs - Monitoring attributes for accuracy/overhead control.
*
- * @sample_interval: The time between access samplings.
+ * @sample_interval: The time between access samplings. Zero is
+ * accepted.
* @aggr_interval: The time between monitor results aggregations.
* @ops_update_interval: The time between monitoring operations updates.
* @intervals_goal: Intervals auto-tuning goal.
--
2.47.3