Messages in this thread | | | Date | Tue, 20 Sep 2005 11:11:17 +0800 | From | liyu <> | Subject | [Question] How to understand Clock-Pro algorithm? |
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Hi, every in LKML/linux-mm:
I have been read CLOCK-Pro paper since last week, and am going to write one python demo.
After just read , I think I can understand it, however once I begin implement it, I found there are many point that not clear.
First, two important parameters Mc, Mh,
In that paper, it assume total memory size is M. (in number of page)
There is a formula:
M = Mc+Mh.
Mc, number of cold pages in memory, Mh, number of hot pages in memory.
So, in clock list, we can keep track 2M page metadatas at most, we may include M non-resident pages.
In '4.3 operationes on searching vicim pages' , the authors said
"we keep track of the number of non-resident cold pages, 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."
My question is out:As this paper words, the number of cold page is total of resident cold pages and non-resident pages. It's the seem number of non-resident cold pages can not beyond M at all!
I also have more questions on CLOCK-Pro. but this question is most doublt for me.
Any clear word is welcome. thank in advanced.
I suppose experience is more important than theory in page-replacement field, is it right?
liyu
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