Andrew Cooper writes:
> On 17/12/2015 20:59, Jonathan Creekmore wrote:
>> Instead of having a manually-curated list of schedulers, use the array
>> that was auto-generated simply by compiling in the scheduler files as
>> the sole source of truth of the available schedulers.
>>
>> CC: George Dunlap <george.dun...@eu.citrix.com>
>> CC: Dario Faggioli <dario.faggi...@citrix.com>
>> Signed-off-by: Jonathan Creekmore <jonathan.creekm...@gmail.com>
>> ---
>> xen/common/schedule.c | 24 +++++++-----------------
>> xen/include/xen/sched-if.h | 5 -----
>> 2 files changed, 7 insertions(+), 22 deletions(-)
>>
>> diff --git a/xen/common/schedule.c b/xen/common/schedule.c
>> index 2f98a48..efbd67d 100644
>> --- a/xen/common/schedule.c
>> +++ b/xen/common/schedule.c
>> @@ -64,20 +64,10 @@ static void poll_timer_fn(void *data);
>> DEFINE_PER_CPU(struct schedule_data, schedule_data);
>> DEFINE_PER_CPU(struct scheduler *, scheduler);
>>
>> -static const struct scheduler *schedulers[] = {
>> -#ifdef CONFIG_SCHED_CREDIT
>> - &sched_credit_def,
>> -#endif
>> -#ifdef CONFIG_SCHED_CREDIT2
>> - &sched_credit2_def,
>> -#endif
>> -#ifdef CONFIG_SCHED_ARINC653
>> - &sched_arinc653_def,
>> -#endif
>> -#ifdef CONFIG_SCHED_RTDS
>> - &sched_rtds_def,
>> -#endif
>> -};
>> +extern const struct scheduler *__schedulers_start[], *__schedulers_end[];
>> +#define NUM_SCHEDULERS
>> (((uintptr_t)__schedulers_end-(uintptr_t)__schedulers_start) \
>> + / sizeof(struct scheduler *))
>> +static const struct scheduler **schedulers = __schedulers_start;
>
> You should be able to play some tricks with getting the linker to set a
> size of a variable it creates, which would hopefully avoid some of this
> complexity.
Yeah, that looks fairly straightforward. I can do that in a v2.
>>
>> static struct scheduler __read_mostly ops;
>>
>> @@ -1468,7 +1458,7 @@ void __init scheduler_init(void)
>>
>> open_softirq(SCHEDULE_SOFTIRQ, schedule);
>>
>> - for ( i = 0; i < ARRAY_SIZE(schedulers); i++ )
>> + for ( i = 0; i < NUM_SCHEDULERS; i++)
>> {
>> if ( schedulers[i]->global_init && schedulers[i]->global_init() < 0
>> )
>> schedulers[i] = NULL;
>> @@ -1479,7 +1469,7 @@ void __init scheduler_init(void)
>> if ( !ops.name )
>> {
>> printk("Could not find scheduler: %s\n", opt_sched);
>> - for ( i = 0; i < ARRAY_SIZE(schedulers); i++ )
>> + for ( i = 0; i < NUM_SCHEDULERS; i++ )
>> if ( schedulers[i] )
>> {
>> ops = *schedulers[i];
>> @@ -1599,7 +1589,7 @@ struct scheduler *scheduler_alloc(unsigned int
>> sched_id, int *perr)
>> int i;
>> struct scheduler *sched;
>>
>> - for ( i = 0; i < ARRAY_SIZE(schedulers); i++ )
>> + for ( i = 0; i < NUM_SCHEDULERS; i++ )
>> if ( schedulers[i] && schedulers[i]->sched_id == sched_id )
>> goto found;
>> *perr = -ENOENT;
>> diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h
>> index 9c6e0f5..66dc9c8 100644
>> --- a/xen/include/xen/sched-if.h
>> +++ b/xen/include/xen/sched-if.h
>> @@ -165,11 +165,6 @@ struct scheduler {
>> void (*tick_resume) (const struct scheduler *, unsigned
>> int);
>> };
>>
>> -extern const struct scheduler sched_credit_def;
>> -extern const struct scheduler sched_credit2_def;
>> -extern const struct scheduler sched_arinc653_def;
>> -extern const struct scheduler sched_rtds_def;
>> -
>
> With these changes, you can make the structures themselves static, which
> would be a nice tidyup.
>
I like that as well and will handle that in the v2.
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