[LTP] [PATCH] memcg/memcg_subgroup_charge: Fix out of memory

[Petr Vorel]

Hi Xiao,

> Since commit f0b9d18, memcg_process maps 33 pages for a process, but
> memory.limit_in_bytes is still restricted to 1 page, so that moving
> the process into group or subgroup results in oom.

> Fixes: f0b9d18 ("memcg/functional: 4.16 kernel updates stat counter in a batch of 33 pages")

> Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
> +++ b/testcases/kernel/controllers/memcg/functional/memcg_subgroup_charge.sh
...
>  testcase_1()
>  {
> -	test_subgroup $PAGESIZE $((2*PAGESIZE))
> +	test_subgroup $PAGESIZES $((2*PAGESIZES))
>  }

>  testcase_2()
>  {
> -	test_subgroup $PAGESIZE $PAGESIZE
> +	test_subgroup $PAGESIZES $PAGESIZES
>  }

>  testcase_3()
>  {
> -	test_subgroup $PAGESIZE 0
> +	test_subgroup $PAGESIZES 0
>  }

>  run_tests

Thanks for your fix, pushed.

BTW some of these tests fail on recent kernel even after these 2 fixes.
They work well on 3.10, but on 4.x fail at least.

Some of the issues has been reported:
* memcg_stat_test.sh
memcg_stat_test 6 TFAIL: hierarchical_memory_limit is 4096, 8192 expected
memcg_stat_test 2 TFAIL: mapped_file is 0, 4096 expected
https://github.com/linux-test-project/ltp/issues/326

* memcg_usage_in_bytes_test.sh
memcg_usage_in_bytes_test 1 TFAIL: memory.usage_in_bytes is 4325376, 4194304 expected
https://github.com/linux-test-project/ltp/issues/326

* memcg_use_hierarchy_test.sh
memcg_use_hierarchy_test 2 TFAIL: echo 1 > memory.use_hierarchy passed unexpectedly
https://github.com/linux-test-project/ltp/issues/93


Kind regards,
Petr