Re: [PATCH v2 03/15] mshyperv: Introduce numa_node_to_proximity_domain_info

[Dave Hansen]

On 8/17/23 17:17, Nuno Das Neves wrote:
>>> +	if (node != NUMA_NO_NODE) {
>>> +		proximity_domain_info.domain_id = node_to_pxm(node);
>>> +		proximity_domain_info.flags.reserved = 0;
>>> +		proximity_domain_info.flags.proximity_info_valid = 1;
>>> +		proximity_domain_info.flags.proximity_preferred = 1;
>>> +	} else {
>>> +		proximity_domain_info.as_uint64 = 0;
>>> +	}
>>> +
>>> +	return proximity_domain_info;
>>> +}
>> Pop quiz: What are the rules for the 30 bits of uninitialized data of
>> proximity_domain_info.flags in the (node != NUMA_NO_NODE) case?
>>
>> I actually don't know off the top of my head.  I generally avoid
>> bitfields, but if they were normal stack-allocated variable space,
>> they'd be garbage.
> I'm not sure what you are getting at here - all the fields are
> initialized.

Whoops, I somehow missed the reserved field initialization.  But, yeah,
a struct would be nice instead of the union here.