Re: [Xen-devel] [PATCH v2 10/48] xen/sched: add scheduler helpers hiding vcpu

[Juergen Gross <jgross@suse.com>]

On 04.09.19 16:49, Jan Beulich wrote:
> On 09.08.2019 16:57, Juergen Gross wrote:
>> Add the following helpers using a sched_unit as input instead of a
>> vcpu:
>>
>> - is_idle_unit() similar to is_idle_vcpu()
>> - is_unit_online() similar to is_vcpu_online()
>> - unit_runnable() like vcpu_runnable()
> 
> Since for vCPU-s within a unit the return values can vary, I think
> it would be nice if you made explicit here what the unit-wide return
> values are meant to mean in such a case (and why the chosen
> alternative is better than the other one).
> 
>> - sched_set_res() to set the current processor of an unit
>> - sched_unit_cpu() to get the current processor of an unit
> 
> What is "the processor of a unit" when there are multiple
> entities within a unit, and hence multiple processors needed
> in order to run the unit?
> 
>> --- a/xen/include/xen/sched-if.h
>> +++ b/xen/include/xen/sched-if.h
>> @@ -59,6 +59,62 @@ static inline void set_sched_res(unsigned int cpu, struct sched_resource *res)
>>       per_cpu(sched_res, cpu) = res;
>>   }
>>   
>> +static inline bool is_idle_unit(const struct sched_unit *unit)
>> +{
>> +    return is_idle_vcpu(unit->vcpu_list);
>> +}
>> +
>> +static inline bool is_unit_online(const struct sched_unit *unit)
>> +{
>> +    return is_vcpu_online(unit->vcpu_list);
>> +}
>> +
>> +static inline bool unit_runnable(const struct sched_unit *unit)
>> +{
>> +    return vcpu_runnable(unit->vcpu_list);
>> +}
>>
>> +static inline void sched_set_res(struct sched_unit *unit,
>> +                                 struct sched_resource *res)
>> +{
>> +    unit->vcpu_list->processor = res->processor;
>> +    unit->res = res;
>> +}
>> +
>> +static inline unsigned int sched_unit_cpu(struct sched_unit *unit)
>> +{
>> +    return unit->res->processor;
>> +}
>> +
>> +static inline void sched_set_pause_flags(struct sched_unit *unit,
>> +                                         unsigned int bit)
>> +{
>> +    __set_bit(bit, &unit->vcpu_list->pause_flags);
>> +}
>> +
>> +static inline void sched_clear_pause_flags(struct sched_unit *unit,
>> +                                           unsigned int bit)
>> +{
>> +    __clear_bit(bit, &unit->vcpu_list->pause_flags);
>> +}
>> +
>> +static inline void sched_set_pause_flags_atomic(struct sched_unit *unit,
>> +                                                unsigned int bit)
>> +{
>> +    set_bit(bit, &unit->vcpu_list->pause_flags);
>> +}
>> +
>> +static inline void sched_clear_pause_flags_atomic(struct sched_unit *unit,
>> +                                                  unsigned int bit)
>> +{
>> +    clear_bit(bit, &unit->vcpu_list->pause_flags);
>> +}
> 
> And with the above - are some/all of these going to remain like
> this, or will they gain for_each-style loops later?

I will add short descriptions to the commit message.


Juergen


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