Re: Background scanning change on 2.4.6-pre1

[Jonathan Morton]

>> > This is going to make all pages have age 0 on an idle system after some
>> > time (the old code from Rik which has been replaced by this code tried to
>> > avoid that)
>
>There's another reason why I think the patch may be ok even without any
>added logic: not only does it simplify the code and remove a illogical
>heuristic, but there is nothing that really says that "age 0" is
>necessarily very bad.

Here's my take on it.  The point of ageing is twofold - to age down pages
that aren't in use, and to age up pages that *are* in use.  So, pages that
are in use will remain with high ages even when background scanning is
being done, and pages that aren't in use will decay to zero age.

I can't see what's wrong with that.  When we need more memory, it's a Very
Good Thing to know that most of the pages in the system haven't been
accessed in yonks - we know exactly which ones we want to throw out first.

--------------------------------------------------------------
from:     Jonathan "Chromatix" Morton
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