Rik van Riel wrote:
> 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.
> 

No, use once logic is good in theory I think. Unfortunately
our implementation is quite fragile IMO (although it seems
to have been "good enough").

This is what I'm currently doing (on top of a couple of other
patches, but you get the idea). I should be able to transform
it into a proper use-once logic if I pick up Nikita's inactive
list second chance bit.