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

[liyu]

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:
>
>  
>
> >    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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