Re: [Question] How to understand Clock-Pro algorithm?

liyu
2005-09-20T05:28:37Z

Hi, All.

In my words, pages in memory is either resident or non-resident.
In linux internal, mapped or unmapped.

So number of non-resident pages is alway less than total number
of pages in memory.

Is your pages physics pages? or, it is Logical pages? However,
I think both is same here.

Waitting for your answer.

Thanks.

liyu

Song Jiang Wrote:

>On Mon, 2005-09-19 at 23:02, liyu wrote:
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>> Let's assume Mn is the total number of non-resident pages in follow
>>words.
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>> Nod, 'M=Mh+Mc' and 'Mc+Mn' < 2M are always true.
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>> Have this implied that Mn is alway less than M? I think so.
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> Yes.
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>> but if "Once the number exceeds M the memory size in number of pages,
>>we terminted the test period of the cold page pointed to by HAND-test."
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>> If Mn is alway less than M, when we move to HAND-test?
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>The algorithm tries to ensure that Mn <= M holds.
>Once Mn == M+1 is detected, run HAND-test to bring it
>back to Mn == M. That is, only during the transition period,
>Mn <= M might not hold, and we make a correction quickly.
>
>So there is no contradiction here.
> Song
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