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From: Rob Landley <rob@landley.net>
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To: =?iso-8859-1?q?J=F6rn=20Engel?= <joern@wohnheim.fh-wedel.de>
Subject: Re: Is there a "make hole" (truncate in middle) syscall?
Date: Fri, 12 Dec 2003 15:37:42 -0600
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On Friday 12 December 2003 08:24, Jörn Engel wrote:

> > ...and it sucks.  Same problem as with updatedb - 99% of all work is
> > bogus, but you don't know which 99%, because the one knowing about it,
> > the kernel, doesn't tell you a thing.
>
> Actually, updatedb sucks even worse.  The database is notoriously
> outdated and each run of updatedb has the effect of flushing the
> cache.  Because of the cache-flushing effect, you cannot even run it
> with maximum niceness.  Running it still hurts you *afterwards*.
>
> Same goes for you userland daemon without kernel support.
>
> Jörn

1) The date optimization, only looking at files newer than the last run, means 
you can avoid looking at 90% of the filesystem.

2) If drop-behind ever gets working, life is good for this sort of thing.  If 
not, there's always O_DIRECT or its replacement (whatever Linus and the 
oracle guy were arguing about last month)...

Rob