diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 550cb967b668..1b3894e861f2 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2701,6 +2701,9 @@ config MEMCPY_SLOW_KUNIT_TEST
 	  and bit ranges. These can be very slow, so they are split out
 	  as a separate config, in case they need to be disabled.
 
+	  Note this config option will be replaced by the use of KUnit test
+	  attributes.
+
 config IS_SIGNED_TYPE_KUNIT_TEST
 	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
 	depends on KUNIT
diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c
index 887926f04731..440aee705ccc 100644
--- a/lib/memcpy_kunit.c
+++ b/lib/memcpy_kunit.c
@@ -551,10 +551,10 @@ static void strtomem_test(struct kunit *test)
 static struct kunit_case memcpy_test_cases[] = {
 	KUNIT_CASE(memset_test),
 	KUNIT_CASE(memcpy_test),
-	KUNIT_CASE(memcpy_large_test),
-	KUNIT_CASE(memmove_test),
-	KUNIT_CASE(memmove_large_test),
-	KUNIT_CASE(memmove_overlap_test),
+	KUNIT_CASE_SLOW(memcpy_large_test),
+	KUNIT_CASE_SLOW(memmove_test),
+	KUNIT_CASE_SLOW(memmove_large_test),
+	KUNIT_CASE_SLOW(memmove_overlap_test),
 	KUNIT_CASE(strtomem_test),
 	{}
 };