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Re: 4k-aligned nodes



On Tue, 7 December 2004 15:30:54 +0000, David Woodhouse wrote:
> On Tue, 2004-12-07 at 15:59 +0100, Jörn Engel wrote:
> > Solution:
> > GC always tries to write out 4k-aligned nodes with 4k of uncompressed
> > data.
> 
> We've been doing that in JFFS2 since February 2001. :)

Ok.  I'll remember that when giving the next presentation.

> > This also causes GC to run into corner-cases and occasionally use more
> > flash footprint than original data.  But in the long run, it should
> > cause data to be in the most efficient format on-flash.
> 
> That's why we have an extra threshold, for the amount of free space
> which is required for GC to merge nodes. See the logic in
> jffs2_garbage_collect_dnode() which expands 'start' and 'end'.

220loc, looks a bit complicated.  If only I had some time to work on
jffs2!

Jörn

-- 
Write programs that do one thing and do it well. Write programs to work
together. Write programs to handle text streams, because that is a
universal interface. 
-- Doug MacIlroy

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