From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andre Przywara <andre.przywara@amd.com>
Subject: Re: Hypervisor crash(!) on xl cpupool-numa-split
Date: Wed, 9 Feb 2011 14:39:30 +0100
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To: Juergen Gross <juergen.gross@ts.fujitsu.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, "Diestelhorst, Stephan" <Stephan.Diestelhorst@amd.com>
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Juergen Gross wrote:
>>> Another interesting thing to note is that the bug happened on pcpu 32,
>>> but there were no advertised migrations from that cpu.
> 
> If I understand the configuration of Andre's machine correctly, pcpu32 will
> be the target of the next migrations. This pcpu is member of the next numa
> node, correct?
No, this is a 6-core box, so the NUMA node span pcpu30-35.
> 
> Could it be there is a problem with the call of domain_update_node_affinity()
> from cpu_disable_scheduler() ?
> 
> Hmm, I think this could really be the problem.
> Andre, could you try the following patch?
Sorry, but that one didn't help. It crashed with the well-known BUG_ON:
(XEN) Xen BUG at sched_credit.c:990
(which is the weight assert in csched_acct (c/s 22858))

Regards,
Andre.

> 
> diff -r f1fac30a531b xen/common/schedule.c
> --- a/xen/common/schedule.c     Wed Feb 09 08:58:11 2011 +0000
> +++ b/xen/common/schedule.c     Wed Feb 09 14:02:12 2011 +0100
> @@ -491,6 +491,10 @@ int cpu_disable_scheduler(unsigned int c
>                           v->domain->domain_id, v->vcpu_id);
>                   cpus_setall(v->cpu_affinity);
>                   affinity_broken = 1;
> +            }
> +            if ( cpus_weight(v->cpu_affinity) < NR_CPUS )
> +            {
> +                cpu_clear(cpu, v->cpu_affinity);
>               }
> 
>               if ( v->processor == cpu )
> 
> 
> Juergen
> 


-- 
Andre Przywara
AMD-OSRC (Dresden)
Tel: x29712