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

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

>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
>CPUs
>> >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
>bounds!
>
>Tristan.

OK, I see. 

Thanks,
Kevin

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