A new DAMON sysfs file for pin-point target removal, namely
obsolete_target, has been added.  Add a test for the functionality.  It
starts DAMON with three monitoring target processes, mark one in the
middle as obsolete, commit it, and confirm the internal DAMON status is
updated to remove the target in the middle.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
 tools/testing/selftests/damon/sysfs.py | 37 ++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/tools/testing/selftests/damon/sysfs.py b/tools/testing/selftests/damon/sysfs.py
index fd8d3698326e..b34aea0a6775 100755
--- a/tools/testing/selftests/damon/sysfs.py
+++ b/tools/testing/selftests/damon/sysfs.py
@@ -279,5 +279,42 @@ def main():
 
     kdamonds.stop()
 
+    # test obsolete_target.
+    proc1 = subprocess.Popen(['sh'], stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+    proc2 = subprocess.Popen(['sh'], stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+    proc3 = subprocess.Popen(['sh'], stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+    kdamonds = _damon_sysfs.Kdamonds(
+            [_damon_sysfs.Kdamond(
+                contexts=[_damon_sysfs.DamonCtx(
+                    ops='vaddr',
+                    targets=[
+                        _damon_sysfs.DamonTarget(pid=proc1.pid),
+                        _damon_sysfs.DamonTarget(pid=proc2.pid),
+                        _damon_sysfs.DamonTarget(pid=proc3.pid),
+                        ],
+                    schemes=[_damon_sysfs.Damos()],
+                    )])])
+    err = kdamonds.start()
+    if err is not None:
+        print('kdamond start failed: %s' % err)
+        exit(1)
+    kdamonds.kdamonds[0].contexts[0].targets[1].obsolete = True
+    kdamonds.kdamonds[0].commit()
+
+    status, err = dump_damon_status_dict(kdamonds.kdamonds[0].pid)
+    if err is not None:
+        print(err)
+        kdamonds.stop()
+        exit(1)
+
+    del kdamonds.kdamonds[0].contexts[0].targets[1]
+
+    assert_ctxs_committed(kdamonds.kdamonds[0].contexts, status['contexts'])
+
+    kdamonds.stop()
+
 if __name__ == '__main__':
     main()
-- 
2.47.3