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From: Jamie Lokier <jamie@shareable.org>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] balloon driver
Date: Sun, 9 Jul 2006 04:02:17 +0100	[thread overview]
Message-ID: <20060709030215.GA10402@mail.shareable.org> (raw)
In-Reply-To: <200607090232.55272.mark.williamson@cl.cam.ac.uk>

Mark Williamson wrote:
> > Even if the guest has to swap, the reasoning is that the guest is in a
> > much better position to figure out what to swap than if the host were
> > forced to.
> 
> Worse, the guest might decide to swap out a page that's already
> swapped in by the host, forcing it to be read in again only to be
> immediately written out to disk by the guest :-(

...unless the guest's disk I/O is with simulated DMA or recognisable
block-copy instruction sequences, and doesn't look at the data.  In
that case the emulator can, in principle, keep track of where pages
are copied around without being examined, and avoid actually swapping
them in.

Probably not worth the complexity.

-- Jamie

  reply	other threads:[~2006-07-09  3:02 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-07-05  2:58 [Qemu-devel] balloon driver Eric L
2006-07-05 14:52 ` Paul Brook
2006-07-09  1:06   ` Eric L
2006-07-09  1:32     ` Mark Williamson
2006-07-09  3:02       ` Jamie Lokier [this message]
2006-07-09 12:42         ` Mark Williamson

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