Re: ~500 megs cached yet 2.6.5 goes into swap hell

[Rik van Riel]

On Thu, 29 Apr 2004, Nick Piggin wrote:

> I'm not very impressed with the pagecache use-once logic, and I
> have a patch to remove it completely and treat non-mapped touches
> (IMO) more sanely.

The basic idea of use-once isn't bad (search for LIRS and
ARC page replacement), however the Linux implementation
doesn't have any of the checks and balances that the
researched replacement algorithms have...

However, adding the checks and balancing required for LIRS,
ARC and CAR(S) isn't easy since it requires keeping track of
a number of recently evicted pages.  That could be quite a 
bit of infrastructure, though it might be well worth it.

-- 
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan

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