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

To: "Tristan Gingold" <Tristan.Gingold@xxxxxxxx>, "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: "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Date: Fri, 21 Apr 2006 15:50:54 +0800
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Thread-topic: [Xen-devel] [PATCH]Check the values of MAX_VIRT_CPUS and NR_CPUSfor SMP
>From: Tristan Gingold [mailto:Tristan.Gingold@xxxxxxxx]
>Sent: 2006年4月21日 15:40
>Le Vendredi 21 Avril 2006 09:28, Tian, Kevin a écrit :
>> From: Tristan Gingold [mailto:Tristan.Gingold@xxxxxxxx]
>> >Sent: 2006年4月21日 15:26
>> >
>> >> >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
>> >than
>> >VCPUs, something goes wrong...
>> Yes, there's only one idle domain now. However I'm not sure
>> why something will go wrong when NR_CPUS > MAX_VIRT_CPUS.
>bvt has per VCPU data.  if #VCPU > #MAX_VIRT_CPUS, bvt
>reads/writes beyond the

OK, I see. 


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