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| author | Johannes Weiner <hannes@cmpxchg.org> | 2023-08-01 09:56:32 -0400 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-08-04 13:03:42 -0700 |
| commit | fac2650276eced3c94bcdbc21d0e5be637c1e582 (patch) | |
| tree | 4a757c2c16d37d5a9b5475305a2d6b51e79eb4b0 /tools | |
| parent | 17457784004c84178798432a029ab20e14f728b1 (diff) | |
| download | lwn-fac2650276eced3c94bcdbc21d0e5be637c1e582.tar.gz lwn-fac2650276eced3c94bcdbc21d0e5be637c1e582.zip | |
selftests: cgroup: fix test_kmem_basic false positives
This test fails routinely in our prod testing environment, and I can
reproduce it locally as well.
The test allocates dcache inside a cgroup, then drops the memory limit
and checks that usage drops correspondingly. The reason it fails is
because dentries are freed with an RCU delay - a debugging sleep shows
that usage drops as expected shortly after.
Insert a 1s sleep after dropping the limit. This should be good
enough, assuming that machines running those tests are otherwise not
very busy.
Link: https://lkml.kernel.org/r/20230801135632.1768830-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/cgroup/test_kmem.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/testing/selftests/cgroup/test_kmem.c b/tools/testing/selftests/cgroup/test_kmem.c index 258ddc565deb..1b2cec9d18a4 100644 --- a/tools/testing/selftests/cgroup/test_kmem.c +++ b/tools/testing/selftests/cgroup/test_kmem.c @@ -70,6 +70,10 @@ static int test_kmem_basic(const char *root) goto cleanup; cg_write(cg, "memory.high", "1M"); + + /* wait for RCU freeing */ + sleep(1); + slab1 = cg_read_key_long(cg, "memory.stat", "slab "); if (slab1 <= 0) goto cleanup; |