Re: [Xen-devel] [PATCH RFC v2 2/2] linux/vnuma: Enables NUMA for domu PV guest

[Elena Ufimtseva <ufimtseva@xxxxxxxxx>]

On Tue, Sep 17, 2013 at 10:37 AM, Dario Faggioli
<dario.faggioli@xxxxxxxxxx> wrote:
> On mar, 2013-09-17 at 15:17 +0100, David Vrabel wrote:
>> On 17/09/13 09:34, Elena Ufimtseva wrote:
>> > After the NUMA topology was received from Xen,
>> > enable NUMA during boot. Should have CONFIG_NUMA
>> > enabled in kernel.
>> >
>> > Changes since v1:
>> > - added additional checks for PV guest and hypercall
>> > support before enablinf NUMA;
>>
>> As I said in response to the other patch, I don't think this does the
>> right thing.
>>
>> I think xen_vnuma_support() needs to try the vnuma hypercall and check
>> it is successful.
>>
> That can surely be done, I think. Elena?

Yes, sure. I will change it.

>
>> > --- a/arch/x86/xen/setup.c
>> > +++ b/arch/x86/xen/setup.c
>> > @@ -20,6 +20,7 @@
>> >  #include <asm/numa.h>
>> >  #include <asm/xen/hypervisor.h>
>> >  #include <asm/xen/hypercall.h>
>> > +#include <asm/xen/vnuma.h>
>> >
>> >  #include <xen/xen.h>
>> >  #include <xen/page.h>
>> > @@ -583,6 +584,9 @@ void __init xen_arch_setup(void)
>> >     WARN_ON(xen_set_default_idle());
>> >     fiddle_vdso();
>> >  #ifdef CONFIG_NUMA
>> > -   numa_off = 1;
>> > +   if (!xen_initial_domain() && xen_vnuma_support())
>>
>> I don't think there's a need to special case the initial domain here is
>> there?
>>
> This is actually something that Konrad asked, since, apparently, there
> are AMD machines that just blows up, as Dom0, if this is on.
>
> Therefore, since, right now, the status of Elena's work is "just DomUs",
> we figured this could be fine for now.
>
> Of course, the final goal (whether for Elena or for someone else to pick
> it up) is to be able to enable vNUMA for Dom0 too, at which point we
> definitely will have to figure out a way to kill this special casing
> safely...
>
> What do you think?
>
> Regards,
> 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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