From mboxrd@z Thu Jan  1 00:00:00 1970
From: George Dunlap <George.Dunlap@eu.citrix.com>
Subject: Re: Hypervisor crash(!) on xl cpupool-numa-split
Date: Tue, 8 Feb 2011 12:08:05 +0000
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To: Juergen Gross <juergen.gross@ts.fujitsu.com>
Cc: Andre Przywara <andre.przywara@amd.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, "Diestelhorst, Stephan" <Stephan.Diestelhorst@amd.com>
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On Tue, Feb 8, 2011 at 5:43 AM, Juergen Gross
<juergen.gross@ts.fujitsu.com> wrote:
> On 02/07/11 16:55, George Dunlap wrote:
>>
>> Juergen,
>>
>> What is supposed to happen if a domain is in cpupool0, and then all of
>> the cpus are taken out of cpupool0? =A0Is that possible?
>
> No. Cpupool0 can't be without any cpu, as Dom0 is always member of cpupoo=
l0.

If that's the case, then since Andre is running this immediately after
boot, he shouldn't be seeing any vcpus in the new pools; and all of
the dom0 vcpus should be migrated to cpupool0, right?  Is it possible
that migration process isn't happening properly?

It looks like schedule.c:cpu_disable_scheduler() will try to migrate
all vcpus, and if it fails to migrate, it returns -EAGAIN so that the
tools will try again.  It's probably worth instrumenting that whole
code-path to make sure it actually happens as we expect.  Are we
certain, for example, that if a hypercall continued on another cpu
will actually return the new error value properly?

Another minor thing: In cpupool.c:cpupool_unassign_cpu_helper(), why
is the cpu's bit set in cpupool_free_cpus without checking to see if
the cpu_disable_scheduler() call actually worked?  Shouldn't that also
be inside the if() statement?

 -George