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

[Harshvardhan Jha]

Hi Michal,

On 16/01/25 2:36 PM, Michal Hocko wrote:
> 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?
>
This test specifically tests the memory cgroup(memcg) subsystem,
focusing on the RSS accounting functionality.

The test verifies how the kernel tracks and reports memory usage within
cgroups, specifically:

- The accuracy of RSS accounting in memory cgroups
- How the kernel updates and maintains the RSS statistics for processes
within memory cgroups
- The proper reporting of memory usage through the cgroup interface

The test typically:

 1. Creates a memory cgroup
 2. Allocates various types of memory within it
 3. Verifies that the reported RSS statistics match the expected values
 4. Test edge cases like shared pages and memory pressure situations

I hope I explained it right @Petr?

Thanks & Regards,
Harshvardhan