Re: [Xenomai-core] Re: [RFC][PATCH 2/2] global CPU affinity control

[Jan Kiszka <jan.kiszka@domain.hid>]

Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> This is version 4 of the /proc/xenomai/affinity feature. It has been
>> rebased on the reworked xnshadow_map code, now applying the default
>> affinity mask in a (hopefully) correct way also on shadow threads.
>>
>> What has been said for the previous patch also applies here: test and
>> comment! Mathias, you asked for this feature, please let us know if it
>> fulfils your requirements.
>>
>> Philippe, you were looking for documentation of this new behaviour.
>> Please let me know where you would like to see this. Surely in the
>> nucleus API, I guess. Anywhere else?
>>
>> Jan
>>
>>
>> ------------------------------------------------------------------------
>> (...)
>> @@ -909,8 +911,8 @@ int xnpod_start_thread(xnthread_t *threa
>>  	if (!testbits(thread->status, XNDORMANT))
>>  		return -EBUSY;
>>  
>> -	if (xnarch_cpus_empty(affinity))
>> -		affinity = XNARCH_CPU_MASK_ALL;
>> +	if (xnarch_cpus_equal(affinity, XNPOD_ALL_CPUS))
>> +		affinity = nkaffinity;
> 
> Should not this be:
> 	if (xnarch_cpus_empty(affinity))
> 		affinity = XNARCH_CPU_MASK_ALL;
> 	xnarch_cpus_and(affinity, affinity, nkaffinity);
> 	if (xnarch_cpus_empty(affinity))
> 		return -EINVAL;
> 
> so that no thread could escape the rule imposed by nkaffinity.
> 

Nope, that's intentional (forgot to repeat this fact, was explained
earlier): Users can always override nkaffinity by their own mask. Only
the "I-don't-care" XNPOD_ALL_CPUS activates this new selection mechanism.

Jan