Re: Re: [RFC][PATCH 1/2] memcg: res_counter hierarchy

From: kamezawa . hiroyu
Date: Mon Jun 09 2008 - 08:03:47 EST


----- Original Message -----
way, breaks limit semantics.
>>>
>> Not easy to use in my point of view. Can we use 'share' in proper way
>> on no-swap machine ?
>>
>
>Not sure I understand your question. Share represents the share of available
>resources.
>

If no swap, you cannot reclaim anonymous pages and shared memory.
Then, the kernel has to abandon any kinds of auto-balancing somewhere.
(just an example. Things will be more complicated when we consinder
mlocked pages and swap-resource-controller.)


>> yield() after callback() means that res_counter's state will be
>> far different from the state after callback.
>> So, we have to yield before call back and check res_coutner sooner.
>>
>
>But does yield() get us any guarantees of seeing the state change?
>
Hmm, myabe my explanation is bad.

in following sequence
1.callback()
2.yield()
3.check usage again
Elapsed time between 1->3 is big.

in following
1.yield()
2.callback()
3.check usage again
Elapsed time between 2->3 is small.

There is an option to implement "changing limit grarually"

Thanks,
-Kame









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