Re: [LTP] [PATCH v3 1/2] API/cgroup: Expose memory_recursiveprot V2 mount opt

[Richard Palethorpe <rpalethorpe@suse.de>]

Hello Michal,

Michal Koutný <mkoutny@suse.com> writes:

> On Tue, Feb 22, 2022 at 12:45:46PM +0000, Richard Palethorpe <rpalethorpe@suse.com> wrote:
>> This changes the effect of trunk nodes' memory.low and memory.min on
>> their leaf nodes. So we need to change the expectations of some tests.
>
> How much are LTP runs striving to not affect environment?

As a general rule we try to leave the environment as we found it so that
testing is more deterministic. For the CGroup testing in particular I
decided not to change anything so that we do not have to worry about how
the init system will react.

> IIRC, the memory_recursiveprot is "remountable"; in the long-term it's
> likely worth watching the memory_recursiveprot behavior only.
>
> I.e. instead of carrying two sets of expectations you can warp the
> environment for the set that's more likely.
>
> Michal

Thinking about it, the reason why I was testing without
memory_recursiveprot is because I'm just direct booting the kernel with
bash as init and running the test. So the LTP is mounting the CGroups
and it should mount with memory_recursiveprot, but it is not.

Probably we have to support older products as well which don't have
memory_recursiveprot enabled and are using V2 (unlikely I guess, but it
is safest to assume this is the case). So we can still run the test, but
report CONF instead of PASS/FAIL. This way we will at least still catch
kernel warnings and panics.

-- 
Thank you,
Richard.

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