Re: [patch] rewrite rd

From: Nick Piggin
Date: Tue Dec 04 2007 - 05:10:30 EST


On Tue, Dec 04, 2007 at 10:54:51AM +0100, Christian Borntraeger wrote:
> Am Dienstag, 4. Dezember 2007 schrieb Nick Piggin:
> [...]
> > There is one slight downside -- direct block device access and filesystem
> > metadata access goes through an extra copy and gets stored in RAM twice.
> > However, this downside is only slight, because the real buffercache of the
> > device is now reclaimable (because we're not playing crazy games with it),
> > so under memory intensive situations, footprint should effectively be the
> > same -- maybe even a slight advantage to the new driver because it can also
> > reclaim buffer heads.
>
> This is just an idea, I dont know if it is worth the trouble, but have you
> though about implementing direct_access for brd? That would allow
> execute-in-place (xip) on brd eliminating the extra copy.

Actually that's a pretty good idea. It would allow xip to be tested
without special hardware as well...

I'll see what the patch looks like. Thanks

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