Re: [PATCH] memcg: Add memory.pressure_level events

[Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>]

>>> +void __init enable_pressure_cgroup(void)
>>> +{
>>> +	WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys,
>>> +				   vmpressure_cgroup_files));
>>> +}
>>
>> There is no functionality discovery going on here, and this is
>> conditional on nothing. Isn't it better then to just add the register +
>> read functions to memcontrol.c and add the files in the memcontrol cftype ?
> 
> I was trying to make the stuff similar to the existing CONFIG_MEMCG_SWAP
> code, which does this kind of adding files to the cgroup. But I can surely
> place files into memcontrol cftype as you suggest.
> 
> Thanks a lot for the comments!
> 
Note that swap can be command line disabled, and in that case we won't
register the files.

Then it makes sense to do it in a separate helper. If I understand your
code correctly, once it is compiled in, it will always be enabled. So I
personally think it is clearer if you register it together with the rest
of the crew.