Re: Background scanning change on 2.4.6-pre1

[Marcelo Tosatti <marcelo@conectiva.com.br>]

(adding linux-mm to the discussion for obvious reasons) 

On Fri, 8 Jun 2001, Linus Torvalds wrote:

> 
> 
> On Fri, 8 Jun 2001, Marcelo Tosatti wrote:
> >
> > Don't you think it would be _much_ easier if we just moved _all_ mapped
> > pages to the active list ?
> 
> But they are..
> 
> Sure, there are anonymous pages, but once they get involved in the MM,
> they _will_ be swap-cached, and moved to the active list
> 
> As to putting anonymous pages on the active list, I don't see any
> advantage, 

Again, the advantage which I can see is that we don't have to "wait" until
anonymous pages get swap-cached (and I really dont think all anonymous
pages will get swapcached) to _then_ start to have a fair aging between
all pages in the system. 

> and Davem tried that once with noticeable performance
> degradation from the added locking and list manipulation.

David, 

Could you please send me that code so I can work on it and try to reduce
the performance degradation and take a look at the what it gives us ?

And remember even if we have a performance degradation by the locking and
list manipulation by adding this "feature", it may bring us a big
advantage on the fair aging thing I described above.


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