Re: [PATCH/RFC] s390: Hypervisor File System

From: Pekka Enberg
Date: Fri Apr 21 2006 - 11:45:57 EST


Hi Michael,

On Fri, 2006-04-21 at 16:08 +0200, Michael Holzheu wrote:
> The first one was, that the hardware interface for getting the data is
> very expensive. We always get back the data for all LPARs and all
> cpus. Therefore we do not want to get the data every time an attribute
> file is read.

You can cache the results in userspace. So I don't see this one as an
argument for making the kernel more complex.

On Fri, 2006-04-21 at 16:08 +0200, Michael Holzheu wrote:
> The second problem was, that we want to provide a consistent snapshot
> of the hypervisor data for the user space application.

How do you ensure consistency now? And how is that different from an
userspace process reading the whole directory hierarchy into cache in
one go?

The update-on-write to special file thing seems bit strange to me. What
if two processes ask for it at the same time?

Pekka

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