linux/tools/testing/selftests/cgroup
David Vernet 830316807e cgroup: remove racy check in test_memcg_sock()
test_memcg_sock() in the cgroup memcg tests, verifies expected memory
accounting for sockets.  The test forks a process which functions as a TCP
server, and sends large buffers back and forth between itself (as the TCP
client) and the forked TCP server.  While doing so, it verifies that
memory.current and memory.stat.sock look correct.

There is currently a check in tcp_client() which asserts memory.current >=
memory.stat.sock.  This check is racy, as between memory.current and
memory.stat.sock being queried, a packet could come in which causes
mem_cgroup_charge_skmem() to be invoked.  This could cause
memory.stat.sock to exceed memory.current.  Reversing the order of
querying doesn't address the problem either, as memory may be reclaimed
between the two calls.  Instead, this patch just removes that assertion
altogether, and instead relies on the values_close() check that follows to
validate the expected accounting.

Link: https://lkml.kernel.org/r/20220423155619.3669555-5-void@manifault.com
Signed-off-by: David Vernet <void@manifault.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-13 07:20:12 -07:00
..
.gitignore tests/cgroup: test cgroup.kill 2021-05-10 10:41:11 -04:00
cgroup_util.c cgroup: account for memory_recursiveprot in test_memcg_low() 2022-05-13 07:20:12 -07:00
cgroup_util.h cgroup: account for memory_recursiveprot in test_memcg_low() 2022-05-13 07:20:12 -07:00
Makefile selftests: cgroup: build error multiple outpt files 2021-12-10 16:46:01 -07:00
test_core.c selftests: cgroup: Test open-time cgroup namespace usage for migration checks 2022-01-06 11:02:29 -10:00
test_freezer.c tests/cgroup: move cg_wait_for(), cg_prepare_for_wait() 2021-05-10 10:41:11 -04:00
test_kill.c tests/cgroup: test cgroup.kill 2021-05-10 10:41:11 -04:00
test_kmem.c kselftests: cgroup: update kmem test for new vmstat implementation 2021-04-30 11:20:38 -07:00
test_memcontrol.c cgroup: remove racy check in test_memcg_sock() 2022-05-13 07:20:12 -07:00
test_stress.sh selftests: cgroup: Run test_core under interfering stress 2019-10-07 07:11:54 -07:00
with_stress.sh selftests: cgroup: Run test_core under interfering stress 2019-10-07 07:11:54 -07:00