[Devel] Re: [PATCH v3 04/13] kmem accounting basic infrastructure

[Glauber Costa]

On 09/27/2012 04:40 PM, Michal Hocko wrote:
> On Thu 27-09-12 16:20:55, Glauber Costa wrote:
>> On 09/27/2012 04:15 PM, Michal Hocko wrote:
>>> On Wed 26-09-12 16:33:34, Tejun Heo wrote:
>>> [...]
>>>>>> So, this seems properly crazy to me at the similar level of
>>>>>> use_hierarchy fiasco.  I'm gonna NACK on this.
>>>>>
>>>>> As I said: all use cases I particularly care about are covered by a
>>>>> global switch.
>>>>>
>>>>> I am laying down my views because I really believe they make more sense.
>>>>> But at some point, of course, I'll shut up if I believe I am a lone voice.
>>>>>
>>>>> I believe it should still be good to hear from mhocko and kame, but from
>>>>> your point of view, would all the rest, plus the introduction of a
>>>>> global switch make it acceptable to you?
>>>>
>>>> The only thing I'm whining about is per-node switch + silently
>>>> ignoring past accounting, so if those two are solved, I think I'm
>>>> pretty happy with the rest.
>>>
>>> I think that per-group "switch" is not nice as well but if we make it
>>> hierarchy specific (which I am proposing for quite some time) and do not
>>> let enable accounting for a group with tasks then we get both
>>> flexibility and reasonable semantic. A global switch sounds too coars to
>>> me and it really not necessary.
>>>
>>> Would this work with you?
>>>
>>
>> How exactly would that work? AFAIK, we have a single memcg root, we
>> can't have multiple memcg hierarchies in a system. Am I missing something?
> 
> Well root is so different that we could consider the first level as the
> real roots for hierarchies.
> 
So let's favor clarity: What you are proposing is that the first level
can have a switch for that, and the first level only. Is that right ?

At first, I just want to understand what exactly is your proposal. This
is not an endorsement of lack thereof.