[RFC PATCH v1.1 6/7] mm/damon/core: update probe hits for new parameter commit

From: SJ Park

Date: Tue Jul 07 2026 - 09:59:00 EST


Users can update DAMON parameters at runtime. If the samples and/or
aggregation intervals are updated in this way, monitoring results
depending on the intervals should also be updated for a more accurate
snapshot. The age and nr_accesses are properly updated, while
probe_hits are not updated in the way. Do the update.

Signed-off-by: SJ Park <sj@xxxxxxxxxx>
---
mm/damon/core.c | 28 +++++++++++++++++++++++++---
mm/damon/tests/core-kunit.h | 13 ++++++++++---
2 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index cda318806b65b..9a3ff0fe55a61 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -898,10 +898,32 @@ static unsigned int damon_nr_samples_for_new_attrs(unsigned int nr_accesses,
new_attrs);
}

+static void damon_update_probe_hits(struct damon_region *r,
+ struct damon_attrs *old_attrs, struct damon_attrs *new_attrs,
+ bool aggregating, struct damon_ctx *ctx)
+{
+ struct damon_probe *p;
+ int i = 0;
+
+ damon_for_each_probe(p, ctx) {
+ r->last_probe_hits[i] = damon_nr_samples_for_new_attrs(
+ r->last_probe_hits[i], old_attrs, new_attrs);
+ if (!aggregating)
+ r->probe_hits[i] = damon_nr_samples_for_new_attrs(
+ r->probe_hits[i], old_attrs,
+ new_attrs);
+ else
+ r->probe_hits[i] = 0;
+ i++;
+ }
+}
+
static void damon_update_monitoring_result(struct damon_region *r,
struct damon_attrs *old_attrs, struct damon_attrs *new_attrs,
- bool aggregating)
+ bool aggregating, struct damon_ctx *ctx)
{
+ damon_update_probe_hits(r, old_attrs, new_attrs, aggregating, ctx);
+
r->last_nr_accesses = damon_nr_samples_for_new_attrs(
r->last_nr_accesses, old_attrs, new_attrs);
if (!aggregating)
@@ -941,8 +963,8 @@ static void damon_update_monitoring_results(struct damon_ctx *ctx,

damon_for_each_target(t, ctx)
damon_for_each_region(r, t)
- damon_update_monitoring_result(
- r, old_attrs, new_attrs, aggregating);
+ damon_update_monitoring_result(r, old_attrs, new_attrs,
+ aggregating, ctx);
}

/*
diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 9e631b19b184a..b4feef1a460f4 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -591,32 +591,39 @@ static void damon_test_update_monitoring_result(struct kunit *test)
.sample_interval = 10, .aggr_interval = 1000,};
struct damon_attrs new_attrs;
struct damon_region *r = damon_new_region(3, 7);
+ struct damon_ctx *ctx;

if (!r)
kunit_skip(test, "region alloc fail");
+ ctx = damon_new_ctx();
+ if (!ctx) {
+ damon_free_region(r);
+ kunit_skip(test, "ctx alloc fail");
+ }

r->nr_accesses = 15;
r->age = 20;

new_attrs = (struct damon_attrs){
.sample_interval = 100, .aggr_interval = 10000,};
- damon_update_monitoring_result(r, &old_attrs, &new_attrs, false);
+ damon_update_monitoring_result(r, &old_attrs, &new_attrs, false, ctx);
KUNIT_EXPECT_EQ(test, r->nr_accesses, 15);
KUNIT_EXPECT_EQ(test, r->age, 2);

new_attrs = (struct damon_attrs){
.sample_interval = 1, .aggr_interval = 1000};
- damon_update_monitoring_result(r, &old_attrs, &new_attrs, false);
+ damon_update_monitoring_result(r, &old_attrs, &new_attrs, false, ctx);
KUNIT_EXPECT_EQ(test, r->nr_accesses, 150);
KUNIT_EXPECT_EQ(test, r->age, 2);

new_attrs = (struct damon_attrs){
.sample_interval = 1, .aggr_interval = 100};
- damon_update_monitoring_result(r, &old_attrs, &new_attrs, false);
+ damon_update_monitoring_result(r, &old_attrs, &new_attrs, false, ctx);
KUNIT_EXPECT_EQ(test, r->nr_accesses, 150);
KUNIT_EXPECT_EQ(test, r->age, 20);

damon_free_region(r);
+ damon_destroy_ctx(ctx);
}

static void damon_test_set_attrs(struct kunit *test)
--
2.47.3