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Re: [Xen-devel] [PATCH][RESUBMIT] don't schedule unplugged vcpus

To: Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH][RESUBMIT] don't schedule unplugged vcpus
From: Ryan Harper <ryanh@xxxxxxxxxx>
Date: Wed, 8 Jun 2005 17:12:47 -0500
Cc: Ryan Harper <ryanh@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
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* Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx> [2005-06-08 17:00]:
> > > I don't see why we care about vcpus that are down. From the user's 
> > > point of view they've gone for good -- it just happens that 
> > Xen hasn't 
> > > freed the memory in anticipation of it being used again. 
> > What do you think?
> > 
> > I don't think the users care so much as I want tools to be 
> > able to extract the current state of affairs for load 
> > balancing or other operations that want to account for domain state.
> I think the vcpu_to_cpu map contains that. 

OK.  I had started doing that, but something stopped me, though I can't
recall what it was at the moment.  I'll mark the down vcpus in the
vcpu_to_cpu map and see if I recall what I thought was objectionable.

> The n_vcpu variable isn't really needed: my inclination would be to just
> report the number that are currently up, though I'm not hugely fussed.

That is an easy change, and we can revert to keeping n_vcpu to the
number of valid vcpus per domain if there in fact is a need.

Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253   T/L: 678-9253

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