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

On 09/27/2012 04:40 PM, Michal Hocko wrote:

On Thu 27-09-12 16:20:55, Glauber Costa wrote:

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On 09/27/2012 04:15 PM, Michal Hocko wrote:

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On Wed 26-09-12 16:33:34, Tejun Heo wrote:
[...]

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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.