>> +- cpupool-sched (optional)
>> +
>> + Must be a string having the name of a Xen scheduler, it has no effect
>> when
>> + used in conjunction of a cpupool-id equal to zero, in that case the
>> + default Xen scheduler is selected (sched=<...> boot argument).
>> + Check the sched=<...> boot argument for allowed values.
>
> I am happy with this version of the device tree bindings, thanks for
> your efforts to update them. Only one comment left: please update the
> description not to include "cpupool-id" given that there is no
> cpupool-id property anymore :-)
>
Hi Stefano,
Thank you for your review,
Yes I missed that! I will fix in the next serie.
>>
>> +/*
>> + * pool_cpu_map: Index is logical cpu number, content is cpupool id, (-1)
>> for
>> + * unassigned.
>> + * pool_sched_map: Index is cpupool id, content is scheduler id, (-1) for
>> + * unassigned.
>> + */
>> +static int __initdata pool_cpu_map[NR_CPUS] = { [0 ... NR_CPUS-1] = -1 };
>> +static int __initdata pool_sched_map[NR_CPUS] = { [0 ... NR_CPUS-1] = -1 };
>> +static unsigned int __initdata next_pool_id;
>> +
>> +#ifdef CONFIG_HAS_DEVICE_TREE
>
> BOOT_TIME_CPUPOOLS depends on HAS_DEVICE_TREE, so it is not possible to
> have BOOT_TIME_CPUPOOLS but not HAS_DEVICE_TREE ?
Yes you are right, the ifdef is not needed at this stage since only arch with
device tree are
using it, if x86 would like to implement a command line version then the code
will be ifdef-ined
later.
>
>
>> +#define BTCPUPOOLS_DT_NODE_NO_REG (-1)
>> +#define BTCPUPOOLS_DT_NODE_NO_LOG_CPU (-2)
>> +
>> +static int __init get_logical_cpu_from_hw_id(unsigned int hwid)
>> +{
>> + unsigned int i;
>> +
>> + for ( i = 0; i < nr_cpu_ids; i++ )
>> + if ( cpu_physical_id(i) == hwid )
>> + return i;
>> +
>> + return -1;
>> +}
>
> I wonder if there is a better way to implement this function but I am
> not sure. Also, it might be better to avoid premature optimizations.
>
> That said, we could check first the simple case where hwid==i. Looking
> at various existing device tree, it seems to be the most common case.
>
> This is not a requirement, just a hand-wavy suggestion. I think the
> patch is also OK as is.
>
Not sure to understand here, at least on FVP (the first DT I have around), hwid
!= i,
Or maybe I didn’t understand what you mean
>
>> +void __init btcpupools_allocate_pools(void)
>> +{
>> + unsigned int i;
>> + bool add_extra_cpupool = false;
>> +
>> + /*
>> + * If there are no cpupools, the value of next_pool_id is zero, so the
>> code
>> + * below will assign every cpu to cpupool0 as the default behavior.
>> + * When there are cpupools, the code below is assigning all the not
>> + * assigned cpu to a new pool (next_pool_id value is the last id + 1).
>> + * In the same loop we check if there is any assigned cpu that is not
>> + * online.
>> + */
>> + for ( i = 0; i < nr_cpu_ids; i++ )
>> + if ( cpumask_test_cpu(i, &cpu_online_map) )
>
> Let me take this opportunity to explain the unfortunately unwritten
> coding style the way I understand it. I know this is tribal knowledge at
> the moment and I apologize for that.
>
> If it is a single line statement, we skip the { }, we keep them in all
> other cases.
>
> So:
>
> /* correct */
> if ( xxx ) {
> something;
> something else;
> }
>
> /* correct */
> if ( xxx ) {
> for ( yyy ) {
> }
> }
>
> /* correct */
> if ( xxx )
> something single line or 2 lines like a printk that go beyond 80
> chars, never in case of nested ifs
>
> /* not correct */
> if ( xxx )
> something
> multi
> line;
>
> /* not correct */
> if ( xxx )
> if ( yyy )
> something;
>
> So basically we would keep the { } here but we would skip them ...
Ok this clarifies a lot, thank you, I will check the code and I will fix it
where it’s not
compliant.
>
>> +#ifdef CONFIG_HAS_DEVICE_TREE
>> +void btcpupools_dtb_parse(void);
>> +#else
>> +static inline void btcpupools_dtb_parse(void) {}
>> +#endif
>
> same comment about !CONFIG_HAS_DEVICE_TREE
Yes I will fix it in the next serie.
Cheers,
Luca
