[v6,0/2] memcg: Fix test_memcg_min/low test failures

Message

Waiman Long April 14, 2025, 2:12 a.m. UTC

v6:
 - The memcg_test_low failure is indeed due to the memory_recursiveprot
   mount option which is enabled by default in systemd cgroup v2 setting.
   So adopt Michal's suggestion to adjust the low event checking
   according to whether memory_recursiveprot is enabled or not.

v5:
 - Use mem_cgroup_usage() in patch 1 as originally suggested by Johannes.

The test_memcontrol selftest consistently fails its test_memcg_low
sub-test (with memory_recursiveprot enabled) and sporadically fails
its test_memcg_min sub-test. This patchset fixes the test_memcg_min
and test_memcg_low failures by skipping the !usage case in
shrink_node_memcgs() and adjust the test_memcontrol selftest to fix
other causes of the test failures.

Waiman Long (2):
  mm/vmscan: Skip memcg with !usage in shrink_node_memcgs()
  selftests: memcg: Increase error tolerance of child memory.current
    check in test_memcg_protection()

 mm/internal.h                                 |  9 +++++++++
 mm/memcontrol-v1.h                            |  2 --
 mm/vmscan.c                                   |  4 ++++
 .../selftests/cgroup/test_memcontrol.c        | 20 ++++++++++++-------
 4 files changed, 26 insertions(+), 9 deletions(-)