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Re: [Xen-devel] [PATCH]Check the values of MAX_VIRT_CPUS and NR_CPUSfor

To: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, "Atsushi SAKAI" <sakaia@xxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH]Check the values of MAX_VIRT_CPUS and NR_CPUSfor SMP
From: Tristan Gingold <Tristan.Gingold@xxxxxxxx>
Date: Fri, 21 Apr 2006 09:26:04 +0200
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Le Vendredi 21 Avril 2006 09:11, Tian, Kevin a écrit :
> From: Keir Fraser
> >Sent: 2006年4月21日 14:41
> >
> >On 21 Apr 2006, at 02:31, Atsushi SAKAI wrote:
> >> But the logical limit of the IA64 Max CPU is larger than 64.
> >> If someone change these values, some possibility make this error
> >
> >again.
> >
> >> To avoid this problem, I believe this check code should be exists.
> >
> >See how we solve this on x86 near the top of do_boot_cpu() in
> >arch/x86/smpboot.c. Essentially we allocate extra idle domains on
> >demand to give us enough idle vcpus for one per physical cpu.
> >
> >  -- Keir
> Yes, that's the same story on ia64 where we also allocate idle
> vcpu at do_boot_cpu(). That's why I'm not sure the real cause
> for Atsushi's issue.
No, we don't create extra domains.  Therefore it there are more CPUs than 
VCPUs, something goes wrong...


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