[OLPC-devel] Re: Announce: Compressed cache 'alpha-002' release

[Jim Gettys]

On Wed, 2006-08-09 at 12:06 +0530, Nitin Gupta wrote:
> Christopher Blizzard wrote:
> > Rik van Riel wrote:
> >> Marcelo isn't currently online due to an accident, but I talked to
> >> him on the phone today.  He said he definately wants to use compressed
> >> swap on OLPC, so I think it would be good if you could work on
> >> stabilizing the current code for use on the OLPC board.
> >>
> >> Open source being what it is, I'm sure somebody will add the page
> >> cache stuff and the adaptive ccache bits.  Especially if they have
> >> a stable base to work from :)
> >>
> >
> > We've talked on and off about allowing some limited swapping to the 
> > flash under emergency circumstances.  But no one has come along with a 
> > concrete way to do that yet.
> >
> I think its already done. When compressed cache reaches its size limit 
> (set by user), pages as sent to swap disks.
> 
> But, if you meant handling wear leveling issues (and maybe others) for 
> swapping over flash, then that is not yet done :) The usual swapping 
> code is still used which aims to minimize disk seeks.
> 

That's ok, I think.  IIRC, IBM released a flash layer recently that will
allow for wear leveling even with multiple partitions.  Dave Woodhouse
hopes to get it set up for us to use.  Even if not, we could swap to
file, where wear leveling would take place.
                              Regards,
                                   - Jim

-- 
Jim Gettys
One Laptop Per Child