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Re: [Xen-devel] [PATCH] vcpu-set increases vcpus beyond the value set at

To: Ryan Grimm <grimm@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] vcpu-set increases vcpus beyond the value set at domain creation
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Thu, 16 Feb 2006 11:49:00 +0000
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On 15 Feb 2006, at 23:04, Ryan Grimm wrote:

This patch allows a domain's vcpus to increase beyond the max (up to
CONFIG_NR_CPUS) set at creation time by making 3 changes:

I'd prefer to keep the current Xen mechanisms, but extend xend and/or config file formats so that we can distinguish max_vcpus from initial_vcpus. Currently the two values are conflated. Then you can set max_vcpus as high as you like, but xenstore will tell the guest how many CPUs to bring up during boot.

If we want a 'hard limit' check in Xen (kind of like we have a per-domain memory limit) to ensure that guests do not sneakily bring up CPUs that we didn't ask them to, then we can add that but it's an orthogonal change (i.e., different patch) to what you are trying to do here.

 -- Keir

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