Re: [Xen-devel] [PATCH RFC v2 1/7] xen/vNUMA: vNUMA support for PV guests.

[Elena Ufimtseva <ufimtseva@xxxxxxxxx>]

On Tue, Sep 17, 2013 at 3:11 AM, Dario Faggioli
<dario.faggioli@xxxxxxxxxx> wrote:
> On mar, 2013-09-17 at 08:05 +0100, Jan Beulich wrote:
>> >>> On 17.09.13 at 08:44, Elena Ufimtseva <ufimtseva@xxxxxxxxx> wrote:
>>
>> Please don't top post.
>>
>> > George, after talking to Dario, I think the max number of physical
>> > nodes will not exceed 256. Dario's automatic NUMA
>> > placement work with this number and I think it can be easily u8.
>> > Unless anyone has other thoughts.
>>
>> With nr_vnodes being uint16_t, the vnode numbers should be
>> too. Limiting them to u8 would possibly be even better, but then
>> nr_vnodes would better be unsigned int (perhaps that was the
>> case from the beginning, regardless of the types used for the
>> arrays).
>>
>> The pnode array surely can also be uint8_t for the time being,
>> considering that there are other places where node IDs are
>> limited to 8 bits.
>>
> All agreed.
>
>> And with struct acpi_table_slit having just 8-bit distances, there's
>> no apparent reason why the virtual distances can't be 8 bits too.
>>
>> But - all this is only for the internal representations. Anything in
>> the public interface should be wide enough to allow future
>> extension.
>>
> And, in fact, 'node_to_node_distance' in xen/include/public/sysctl.h
> (http://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/include/public/sysctl.h)
> is uint32.
>

Linux has u8 for distance. Ok, thank you for pointing that out.

Elena

> Dario
>
> --
> <<This happens because I choose it to happen!>> (Raistlin Majere)
> -----------------------------------------------------------------
> Dario Faggioli, Ph.D, http://about.me/dario.faggioli
> Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
>



-- 
Elena

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