Re: [RFC][PATCH 0/2] memcg: hierarchy support (v3)

From: Balbir Singh
Date: Mon Jun 09 2008 - 06:34:21 EST


KAMEZAWA Hiroyuki wrote:
> On Mon, 09 Jun 2008 15:00:22 +0530
> Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
>
>> KAMEZAWA Hiroyuki wrote:
>>> Hi, this is third version.
>>>
>>> While small changes in codes, the whole _tone_ of code is changed.
>>> I'm not in hurry, any comments are welcome.
>>>
>>> based on 2.6.26-rc2-mm1 + memcg patches in -mm queue.
>>>
>> Hi, Kamezawa-San,
>>
>> Sorry for the delay in responding. Like we discussed last time, I'd prefer a
>> shares based approach for hierarchial memcg management. I'll review/try these
>> patches and provide more feedback.
>>
> Hi,
>
> I'm now totally re-arranging patches, so just see concepts.
>
> In previous e-mail, I thought that there was a difference between 'your share'
> and 'my share'. So, please explain again ?
>
> My 'share' has following characteristics.
>
> - work as soft-limit. not hard-limit.
> - no limit when there are not high memory pressure.
> - resource usage will be proportionally fair to each group's share (priority)
> under memory pressure.
>

My share is very similar to yours.

A group might have a share of 100% and a hard limit of 1G. In this case the hard
limit applies if the system has more than 1G of memory. I think of hard limit as
the final controlling factor and shares are suggestive.

Yes, my shares also have the same factors, but can be overridden by hard limits.


> If you want to work on this, I can stop this for a while and do other important
> patches, like background reclaim, mlock limitter, guarantee, etc.. because my
> priority to hierarchy is not very high (but it seems better to do this before
> other misc works, so I did.).
>

I do, but I don't want to stop you from doing it. mlock limitter is definitely
important, along with some control for large pages. Hierarchy is definitely
important, since we cannot add other major functionality without first solving
this proble, After that, High on my list is

1. Soft limits
2. Performance/space trade-offs

> Anyway, we have to test the new LRU (RvR LRU) at first in the next -mm ;)

Yes :) I just saw that going in


--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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