[v4,0/2] memcg: Fix test_memcg_min/low test failures

Message

Waiman Long April 7, 2025, 1:41 a.m. UTC

v3:
 - Take up Johannes' suggestion of just skip the !usage case and
   fix test_memcontrol selftest to fix the rests of the min/low
   failures.
v4:
 - Add "#ifdef CONFIG_MEMCG" directives around shrink_node_memcgs() to
   avoid compilation problem with !CONFIG_MEMCG configs.

The test_memcontrol selftest consistently fails its test_memcg_low
sub-test 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.

Note that I decide not to use the suggested mem_cgroup_usage() call as
it is a real function call defined in mm/memcontrol.c to be used mainly
by cgroup v1 code.

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/vmscan.c                                      | 10 ++++++++++
 tools/testing/selftests/cgroup/test_memcontrol.c | 11 ++++++++---
 2 files changed, 18 insertions(+), 3 deletions(-)