Re: [Xen-devel] [RFC PATCH v3 10/24] NUMA: Allow numa initialization with DT

[Vijay Kilari <vijay.kilari@xxxxxxxxx>]

On Wed, Jul 19, 2017 at 11:28 PM, Julien Grall <julien.grall@xxxxxxx> wrote:
> Hi Vijay,
>
> On 18/07/17 12:41, vijay.kilari@xxxxxxxxx wrote:
>>
>> From: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxx>
>>
>> The common code allows numa initialization only when
>> ACPI_NUMA config is enabled. Allow initialization when
>> NUMA config is enabled for DT.
>>
>> In this patch, along with acpi_numa, check for acpi_disabled
>> is added.
>>
>> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxx>
>> ---
>>  xen/common/numa.c | 4 +---
>>  1 file changed, 1 insertion(+), 3 deletions(-)
>>
>> diff --git a/xen/common/numa.c b/xen/common/numa.c
>> index 74c4697..5e985d2 100644
>> --- a/xen/common/numa.c
>> +++ b/xen/common/numa.c
>> @@ -324,7 +324,7 @@ static int __init numa_scan_nodes(paddr_t start,
>> paddr_t end)
>>      for ( i = 0; i < MAX_NUMNODES; i++ )
>>          cutoff_node(i, start, end);
>>
>> -    if ( acpi_numa <= 0 )
>> +    if ( !acpi_disabled && acpi_numa <= 0 )
>
>
> I am struggling to understand this change. Likely you want to similar
> variable for DT to say NUMA is available or this has failed.

Yes, without this check for acpi_disabled, when booting with DT, the check
acpi_numa <= 0 is true and does not allow numa initialization.

>
> This also change quite a bit the semantic for x86 because, you will now
> continue if acpi_disabled and acpi_numa = 0. The code seems to allow it, but
> I don't know if we support it.

Yes, but prior to this patch, x86 is assuming that acpi_disabled is
false by checking
only for acpi_numa <=0.

The other solution is create a arch wrapper and call this from here.

Regards
Vijay


>
> Cheers,
>
> --
> Julien Grall

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