> > Linux VM, but we don't need that functionality: in Linux we have always
> > swapped out ptes on a per-page-table basis, not on a per-physical-page
> > basis. We *DO* swap processes out independently.
>
> I dont think I understand. The whole idea of doing it globally is
> to do some kind of LRU on a global scale and swap out pages based
> on that.
This terribly fragments swap space -- you seem to be forgetting
that we also need to swap things back _in_ and that is most
efficient when the process' pages are contiguous on disk.
LRU is just a good guess, the method Linux uses might be a bit
worse on swap-out, but since we do less disk _seek_ I/O we come
out slightly ahead of the normal way...
For Linux 2.3 we are planning several major enhancements to
this scheme though (much better I/O clustering and swap read-
ahead/behind and several other goodies).
cheers,
Rik -- the flu hits, the flu hits, the flu hits -- MORE
+-------------------------------------------------------------------+
| Linux memory management tour guide. H.H.vanRiel@phys.uu.nl |
| Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ |
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