diff --git a/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_wss_estimation.py b/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_wss_estimation.py
index 90ad7409a7a6..bf48ef8e5241 100755
--- a/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_wss_estimation.py
+++ b/tools/testing/selftests/damon/sysfs_update_schemes_tried_regions_wss_estimation.py
@@ -6,9 +6,8 @@ import time
 
 import _damon_sysfs
 
-def main():
-    # access two 10 MiB memory regions, 2 second per each
-    sz_region = 10 * 1024 * 1024
+def pass_wss_estimation(sz_region):
+    # access two regions of given size, 2 seocnds per each region
     proc = subprocess.Popen(['./access_memory', '2', '%d' % sz_region, '2000'])
     kdamonds = _damon_sysfs.Kdamonds([_damon_sysfs.Kdamond(
             contexts=[_damon_sysfs.DamonCtx(
@@ -36,20 +35,38 @@ def main():
 
         wss_collected.append(
                 kdamonds.kdamonds[0].contexts[0].schemes[0].tried_bytes)
+    err = kdamonds.stop()
+    if err is not None:
+        print('kdamond stop failed: %s' % err)
+        exit(1)
 
     wss_collected.sort()
     acceptable_error_rate = 0.2
     for percentile in [50, 75]:
         sample = wss_collected[int(len(wss_collected) * percentile / 100)]
         error_rate = abs(sample - sz_region) / sz_region
-        print('%d-th percentile (%d) error %f' %
-                (percentile, sample, error_rate))
+        print('%d-th percentile error %f (expect %d, result %d)' %
+                (percentile, error_rate, sz_region, sample))
         if error_rate > acceptable_error_rate:
             print('the error rate is not acceptable (> %f)' %
                     acceptable_error_rate)
             print('samples are as below')
             print('\n'.join(['%d' % wss for wss in wss_collected]))
-            exit(1)
+            return False
+    return True
+
+def main():
+    # DAMON doesn't flush TLB.  If the system has large TLB that can cover
+    # whole test working set, DAMON cannot see the access.  Test up to 160 MiB
+    # test working set.
+    sz_region_mb = 10
+    max_sz_region_mb = 160
+    while sz_region_mb <= max_sz_region_mb:
+        test_pass = pass_wss_estimation(sz_region_mb * 1024 * 1024)
+        if test_pass is True:
+            exit(0)
+        sz_region_mb *= 2
+    exit(1)
 
 if __name__ == '__main__':
     main()