Re: [patch] 4GB I/O, cut three

From: Jens Axboe (
Date: Wed May 30 2001 - 09:06:53 EST

On Wed, May 30 2001, Andrea Arcangeli wrote:
> > > I did change the patch so that bounce-pages always come from the NORMAL
> > > zone, hence the ZONE_DMA32 zone isn't needed. I avoided the new zone, as
> > > I'm not 100% sure the VM is capable of keeping the zones it already has
> > > balanced - and adding another one might break the camels back. But as the
> > > test box has 4GB, it wasn't bouncing anyway.
> >
> > You are right, this is definitely something that needs checking. I
> > really want this to work though. Rik, Andrea? Will the balancing handle
> > the extra zone?
> The bounces can came from the ZONE_NORMAL without problems, however the

Of course

> ZONE_DMA32 way is fine too, but yes probably it isn't needed in real
> life unless you do an huge amount of I/O at the same time. If you want

It's not strictly needed, but it does buy us 3 extra gig to do I/O from
an a pae enabled x86.

> to reduce the amount of changes you can defer the zone_dma32 patch and
> possibly plug it in later.

Yes, I did modular patches for this reason.


Jens Axboe

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