[LTP] Issue faced in memcg_stat_rss while running mainline kernels between 6.7 and 6.8

[Petr Vorel]

Hi Michal, all,

> On Thu 16-01-25 13:37:14, Harshvardhan Jha wrote:
> > Hello Michal
> > On 16/01/25 1:23 PM, Michal Hocko wrote:
> > > Hi,

> > > On Wed 15-01-25 23:59:20, Petr Vorel wrote:
> > >> Hi Harshvardhan,

> > >> [ Cc cgroups@vger.kernel.org: FYI problem in recent kernel using cgroup v1 ]
> > > It is hard to decypher the output and nail down actual failure. Could
> > > somebody do a TL;DR summary of the failure, since when it happens, is it
> > > really v1 specific?

> > The test ltp_memcg_stat_rss is indeed cgroup v1 specific.

> What does this test case aims to test?

I'm not an expert on cgroup tests, maybe Li or Cyril will comment better.

memcg_stat_rss.sh [1] claims "Test the management and counting of memory",
test_mem_stat() [2] checks memory.stat doing some memory allocation.
Each test runs memcg_process.c [3], which does various mmap(),
followed by checks.

These tests are quite old, not sure how relevant they are. We have newer tests
written completely in C, which are more reliable.

Kind regards,
Petr

[1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/controllers/memcg/functional/memcg_stat_rss.sh#L17C3-L17C45
[2] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/controllers/memcg/functional/memcg_lib.sh#L249
[3] https://github.com/linux-test-project/ltp/tree/master/testcases/kernel/controllers/memcg/functional/memcg_process.c