Near the end of test_memcg_protection(), reclaim_until() is called to reduce memory.current of children[0] to 10M. It was found that with larger page size (e.g. 64k) the various memory cgroups in test_memcg_protection() would deviate further from the expected values especially for the test_memcg_low test. As a result, children[0] might have reached the target already without reclamation. The will cause the reclaim_until() function to report failure as no reclamation is needed.
Avoid this unexpected failure by skipping the reclaim_until() call if memory.current of children[0] has already reached the target size for kernel with non-4k page size. Signed-off-by: Waiman Long <[email protected]> --- tools/testing/selftests/cgroup/test_memcontrol.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c index 4f12d4b4f9f8..0ef09bafa68c 100644 --- a/tools/testing/selftests/cgroup/test_memcontrol.c +++ b/tools/testing/selftests/cgroup/test_memcontrol.c @@ -490,6 +490,7 @@ static int test_memcg_protection(const char *root, bool min) long current; int i, attempts; int fd; + bool do_reclaim; fd = get_temp_fd(); if (fd < 0) @@ -602,7 +603,15 @@ static int test_memcg_protection(const char *root, bool min) 9 + (min ? 0 : 6) * pscale_factor)) goto cleanup; - if (!reclaim_until(children[0], MB(10))) + /* + * With larger page size, it is possible that memory.current of + * children[0] is close to 10M. Skip the reclaim_until() call if + * that is the case. + */ + current = cg_read_long(children[0], "memory.current"); + do_reclaim = (page_size == KB(4)) || + ((current > MB(10)) && !values_close(current, MB(10), 3)); + if (do_reclaim && !reclaim_until(children[0], MB(10))) goto cleanup; if (min) { -- 2.53.0
