From mboxrd@z Thu Jan  1 00:00:00 1970
From: Juergen Gross <juergen.gross@ts.fujitsu.com>
Subject: Re: Cpu pools discussion
Date: Fri, 31 Jul 2009 07:25:37 +0200
Message-ID: <4A728051.4010807@ts.fujitsu.com>
References: <C6975C18.10F02%keir.fraser@eu.citrix.com>
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To: Keir Fraser <keir.fraser@eu.citrix.com>
Cc: Tim Deegan <Tim.Deegan@eu.citrix.com>, George Dunlap <dunlapg@umich.edu>, Zhigang Wang <zhigang.x.wang@oracle.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
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Keir Fraser wrote:
> On 30/07/2009 13:51, "Juergen Gross" <juergen.gross@ts.fujitsu.com> wrote:
> 
>>> I think especially if cpupools are added into the mix then this becomes more
>>> attractive than the current approach. The other alternative is to modify the
>>> two existing problematic callers to work okay from softirq context (or not
>>> need continue_hypercall_on_cpu() at all, which might be possible at least in
>>> the case of CPU hotplug). I would be undecided between these two just now --
>>> it depends on how easily those two callers can be fixed up.
>> I'll try to set up a patch to add a hypervisor domain. Regarding all the
>> problems I got with switching cpus between pools (avoid running on the cpu to
>> be switched etc.) this solution could make life much easier.
> 
> I'm inclined actually to think a hypervisor domain is not necessary, and we
> can get by with softirqs. I actually think cpu offline can be reimplemented
> without softirqs or continue_hypercall_on_cpu(), and I would imagine cpupool
> changes then could use a similar technique. I will take a look at that, and
> you can take your cues from it if I find an elegant solution along those
> lines.

Thanks, that's great!


Juergen

-- 
Juergen Gross                 Principal Developer Operating Systems
TSP ES&S SWE OS6                       Telephone: +49 (0) 89 636 47950
Fujitsu Technolgy Solutions               e-mail: juergen.gross@ts.fujitsu.com
Otto-Hahn-Ring 6                        Internet: ts.fujitsu.com
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