[RFC PATCH 10/14] mm/damon/tests/core-kunit: add damon_set_regions() test cases

[SeongJae Park <sj@kernel.org>]

damon_set_regions() is one of the main DAMON kernel API functions that
set up the monitoring target memory region boundaries.  Implement unit
tests for verifying its basic functionalities.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 mm/damon/tests/core-kunit.h | 142 ++++++++++++++++++++++++++++++------
 1 file changed, 120 insertions(+), 22 deletions(-)

diff --git a/mm/damon/tests/core-kunit.h b/mm/damon/tests/core-kunit.h
index 866f716e5760d..1cfb8c176b873 100644
--- a/mm/damon/tests/core-kunit.h
+++ b/mm/damon/tests/core-kunit.h
@@ -390,41 +390,139 @@ static void damon_test_ops_registration(struct kunit *test)
 	}
 }
 
-static void damon_test_set_regions(struct kunit *test)
+static void damon_test_set_regions_for(struct kunit *test,
+		struct damon_addr_range *old_ranges, int sz_old_ranges,
+		struct damon_addr_range *new_ranges, int sz_new_ranges,
+		unsigned long min_region_sz,
+		struct damon_addr_range *expect_ranges, int sz_expect_ranges)
 {
-	struct damon_target *t = damon_new_target();
-	struct damon_region *r1, *r2;
-	struct damon_addr_range range = {.start = 8, .end = 28};
-	unsigned long expects[] = {8, 16, 16, 24, 24, 28};
-	int expect_idx = 0;
+	struct damon_target *t;
 	struct damon_region *r;
+	int i;
 
+	t = damon_new_target();
 	if (!t)
 		kunit_skip(test, "target alloc fail");
-	r1 = damon_new_region(4, 16);
-	if (!r1) {
-		damon_free_target(t);
-		kunit_skip(test, "region alloc fail");
-	}
-	r2 = damon_new_region(24, 32);
-	if (!r2) {
-		damon_free_target(t);
-		damon_free_region(r1);
-		kunit_skip(test, "second region alloc fail");
+	for (i = 0; i < sz_old_ranges; i++) {
+		r = damon_new_region(old_ranges[i].start, old_ranges[i].end);
+		if (!r) {
+			damon_destroy_target(t, NULL);
+			kunit_skip(test, "%d-th r alloc fail\n", i);
+		}
+		damon_add_region(r, t);
 	}
 
-	damon_add_region(r1, t);
-	damon_add_region(r2, t);
-	damon_set_regions(t, &range, 1, 1);
+	damon_set_regions(t, new_ranges, sz_new_ranges, min_region_sz);
 
-	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), 3);
+	KUNIT_EXPECT_EQ(test, damon_nr_regions(t), sz_expect_ranges);
+	if (damon_nr_regions(t) != sz_expect_ranges) {
+		damon_destroy_target(t, NULL);
+		return;
+	}
+	i = 0;
 	damon_for_each_region(r, t) {
-		KUNIT_EXPECT_EQ(test, r->ar.start, expects[expect_idx++]);
-		KUNIT_EXPECT_EQ(test, r->ar.end, expects[expect_idx++]);
+		KUNIT_EXPECT_EQ(test, r->ar.start, expect_ranges[i].start);
+		KUNIT_EXPECT_EQ(test, r->ar.end, expect_ranges[i++].end);
 	}
+
 	damon_destroy_target(t, NULL);
 }
 
+static void damon_test_set_regions(struct kunit *test)
+{
+	/* Initial build up on empty target. */
+	damon_test_set_regions_for(test,
+			(struct damon_addr_range[]){}, 0,
+			(struct damon_addr_range[]){
+			{.start = 5, .end = 15},
+			{.start = 15, .end = 25},
+			}, 2,
+			1,
+			(struct damon_addr_range[]){
+			{.start = 5, .end = 15},
+			{.start = 15, .end = 25},
+			}, 2);
+	/* Un-intersecting regions should be removed. */
+	damon_test_set_regions_for(test,
+			(struct damon_addr_range[]){
+			{.start = 4, .end = 16},
+			{.start = 24, .end = 32},
+			}, 2,
+			(struct damon_addr_range[]){
+			{.start = 18, .end = 23},
+			}, 1,
+			1,
+			(struct damon_addr_range[]){
+			{.start = 18, .end = 23},
+			}, 1);
+	/*
+	 * Holes should be filled up with new regions.
+	 *
+	 * old:       [4,   16)        [24,     32)
+	 * new:         [8,                 28)
+	 * expect:      [8, 16)[16,24),[24, 28)
+	 */
+	damon_test_set_regions_for(test,
+			(struct damon_addr_range[]){
+			{.start = 4, .end = 16},
+			{.start = 24, .end = 32},
+			}, 2,
+			(struct damon_addr_range[]){
+			{.start = 8, .end = 28},
+			}, 1,
+			1,
+			(struct damon_addr_range[]){
+			{.start = 8, .end = 16},
+			{.start = 16, .end = 24},
+			{.start = 24, .end = 28},
+			}, 3);
+	/*
+	 * New regions should be able to be appended.
+	 *
+	 * old:       [0, 4)[4,    17)
+	 * new:       [0,       15)     [25, 40)
+	 * expect:    [0, 4)[4, 15)     [25, 40)
+	 */
+	damon_test_set_regions_for(test,
+			(struct damon_addr_range[]){
+			{.start = 0, .end = 4},
+			{.start = 4, .end = 17},
+			}, 2,
+			(struct damon_addr_range[]){
+			{.start = 0, .end = 15},
+			{.start = 25, .end = 40},
+			}, 2,
+			1,
+			(struct damon_addr_range[]){
+			{.start = 0, .end = 4},
+			{.start = 4, .end = 15},
+			{.start = 25, .end = 40},
+			}, 3);
+	/*
+	 * New regions should be able to be inserted.
+	 *
+	 * old:       [0, 4)                      [42,    52)
+	 * new:       [0,       15)     [25, 40)    [44, 50)
+	 * expect:    [0,       15)     [25, 40)    [44, 50)
+	 */
+	damon_test_set_regions_for(test,
+			(struct damon_addr_range[]){
+			{.start = 0, .end = 4},
+			{.start = 42, .end = 52},
+			}, 2,
+			(struct damon_addr_range[]){
+			{.start = 0, .end = 15},
+			{.start = 25, .end = 40},
+			{.start = 44, .end = 50},
+			}, 3,
+			1,
+			(struct damon_addr_range[]){
+			{.start = 0, .end = 15},
+			{.start = 25, .end = 40},
+			{.start = 44, .end = 50},
+			}, 3);
+}
+
 static void damon_test_nr_accesses_to_accesses_bp(struct kunit *test)
 {
 	struct damon_attrs attrs = {
-- 
2.47.3