[RFC PATCH 5/8] mm/damon/core-test: add a unit test for the feedback loop algorithm

SeongJae Park
2023-11-12T19:46:35Z

Implement a simple kunit test for testing the behavior of the core logic
of the goal-oriented feedback-driven DAMOS quota auto-tuning.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/damon/core-test.h | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)

diff --git a/mm/damon/core-test.h b/mm/damon/core-test.h
index f405d79dc623..c2b8cb25a195 100644
--- a/mm/damon/core-test.h
+++ b/mm/damon/core-test.h
@@ -447,6 +447,37 @@ static void damos_test_filter_out(struct kunit *test)
damos_free_filter(f);
}

+static void damon_test_feed_loop_next_input(struct kunit *test)
+{
+ unsigned long last_input = 900000, current_score = 200;
+
+ /*
+ * If current score is lower than the goal, which is always 10,000
+ * (read the comment on damon_feed_loop_next_input()'s comment), next
+ * input should be higher than the last input.
+ */
+ KUNIT_EXPECT_GT(test,
+ damon_feed_loop_next_input(last_input, current_score),
+ last_input);
+
+ /*
+ * If current score is higher than the goal, next input should be lower
+ * than the last input.
+ */
+ current_score = 250000000;
+ KUNIT_EXPECT_LT(test,
+ damon_feed_loop_next_input(last_input, current_score),
+ last_input);
+
+ /*
+ * The next input depends on the distance between the current score and
+ * the goal
+ */
+ KUNIT_EXPECT_GT(test,
+ damon_feed_loop_next_input(last_input, 200),
+ damon_feed_loop_next_input(last_input, 2000));
+}
+
static struct kunit_case damon_test_cases[] = {
KUNIT_CASE(damon_test_target),
KUNIT_CASE(damon_test_regions),
@@ -463,6 +494,7 @@ static struct kunit_case damon_test_cases[] = {
KUNIT_CASE(damon_test_moving_sum),
KUNIT_CASE(damos_test_new_filter),
KUNIT_CASE(damos_test_filter_out),
+ KUNIT_CASE(damon_test_feed_loop_next_input),
{},
};

--
2.34.1