Re: An idea for prefetching swapped memory...

[Thomas Schlichter <schlicht@rumms.uni-mannheim.de>]

Quoting Måns Rullgård <mru@users.sourceforge.net>:

> Thomas Schlichter <schlicht@rumms.uni-mannheim.de> writes:
> > What I wanted to say is that if there is free memory it should be
> > filled with the pages that were in use before the memory got
> > rare. And these are the pages swapped out last. The other swapped
> > out pages are swapped out even longer and so will likely not be used
> > in the near future... (That's what the LRU algorithm says...)
> 
> Would it be possible to track the most recently used swapped out page?
> This would possibly be a good candidate for speculative loading.

Well, I think the 'more recently used swapped out' order relation is equivalent
to the 'later swapped out' order relation if the kswapd uses the LRU algorithm.
(if it does not, it has its reasons and we should respect them by simply using
the 'later swapped out' order...)

But I am not familiar with the linux swapping management so I don't know if it
tracks this order in any structure. Perhaps there is a kind of 'last used
timestamp' for each page and so for the swapped pages, too, wich could be used
for my purpose. But as I sayed, I don't know...

I hope there is anybody out there who can help me with this question...

Thanks 
   Thomas