[LTP] [PATCH v1] memcontrol03: Using clean page cache to avoid dependency on IO rate

[Wei Gao]

Bad IO situation(storage bandwidth ~10MB/sec) will lead background
writeback has uncertain progress for dirty page. So system can not
reclaim enough memory for new process and finally lead a unexpected
OOM.

memcontrol03.c:218: TPASS: Expect: (A/B/E memory.current=0) ~= 0
memcontrol03.c:116: TPASS: Child 1918 killed by OOM
memcontrol03.c:224: TPASS: Expect: (A/B memory.current=52588544) ~= 52428800
memcontrol03.c:129: TFAIL: Expected child 1944 to exit(0), but instead killed by SIGKILL

Signed-off-by: Wei Gao <wegao@suse.com>
---
 testcases/kernel/controllers/memcg/memcontrol03.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/testcases/kernel/controllers/memcg/memcontrol03.c b/testcases/kernel/controllers/memcg/memcontrol03.c
index 9c6c808e0..9903ba82b 100644
--- a/testcases/kernel/controllers/memcg/memcontrol03.c
+++ b/testcases/kernel/controllers/memcg/memcontrol03.c
@@ -201,6 +201,7 @@ static void test_memcg_min(void)
 		sleep(1);
 	}
 
+	sync();
 	alloc_anon_in_child(trunk_cg[G], MB(148), 0);
 
 	SAFE_CG_SCANF(trunk_cg[B], "memory.current", "%ld", c);
@@ -217,6 +218,7 @@ static void test_memcg_min(void)
 	TST_EXP_EXPR(values_close(c[2], 0, 1),
 		     "(A/B/E memory.current=%ld) ~= 0", c[2]);
 
+	sync();
 	alloc_anon_in_child(trunk_cg[G], MB(170), 1);
 
 	SAFE_CG_SCANF(trunk_cg[B], "memory.current", "%ld", c);
-- 
2.35.3