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

[Song Jiang]

On Mon, 2005-09-19 at 23:02, liyu wrote:

> 
>     Let's assume Mn is the total number of non-resident pages in follow 
> words.
> 
>     Nod, 'M=Mh+Mc' and 'Mc+Mn' < 2M are always true.
> 
>     Have this implied that Mn is alway less than M? I think so.
    Yes.

> 
>     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."
> 
>     If Mn is alway less than M, when we move to HAND-test?

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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