[PATCH 10/12] scheduler: Simplify simple scheduler

[Gedare Bloom]

On Thu, Jun 13, 2013 at 12:01 PM, Gedare Bloom <gedare at rtems.org> wrote:
> On Wed, Jun 12, 2013 at 11:29 AM, Sebastian Huber
> <sebastian.huber at embedded-brains.de> wrote:
>> Add and use _Scheduler_simple_Insert_as_first_order(),
>> _Scheduler_simple_Insert_as_last_order(),
>> _Scheduler_simple_Insert_as_first() and
>> _Scheduler_simple_Insert_as_last().
>> ---
>>  .../score/inline/rtems/score/schedulersimple.inl   |   46 ++++++++++++++++++++
>>  .../score/src/schedulersimplereadyqueueenqueue.c   |   21 +--------
>>  .../src/schedulersimplereadyqueueenqueuefirst.c    |   26 +----------
>>  3 files changed, 50 insertions(+), 43 deletions(-)
>>
>> diff --git a/cpukit/score/inline/rtems/score/schedulersimple.inl b/cpukit/score/inline/rtems/score/schedulersimple.inl
>> index e67fc3c..1b58c85 100644
>> --- a/cpukit/score/inline/rtems/score/schedulersimple.inl
>> +++ b/cpukit/score/inline/rtems/score/schedulersimple.inl
>> @@ -48,6 +48,52 @@ RTEMS_INLINE_ROUTINE void _Scheduler_simple_Ready_queue_requeue(
>>    _Scheduler_simple_Ready_queue_enqueue( the_thread );
>>  }
>>
>> +RTEMS_INLINE_ROUTINE bool _Scheduler_simple_Insert_as_first_order(
>> +  const Chain_Node *to_insert,
>> +  const Chain_Node *next
>> +)
>> +{
>> +  const Thread_Control *thread_to_insert = (const Thread_Control *) to_insert;
>> +  const Thread_Control *thread_next = (const Thread_Control *) next;
>> +
>> +  return thread_to_insert->current_priority <= thread_next->current_priority;
>> +}
>> +
>> +RTEMS_INLINE_ROUTINE bool _Scheduler_simple_Insert_as_last_order(
>> +  const Chain_Node *to_insert,
>> +  const Chain_Node *next
>> +)
>> +{
>> +  const Thread_Control *thread_to_insert = (const Thread_Control *) to_insert;
>> +  const Thread_Control *thread_next = (const Thread_Control *) next;
>> +
>> +  return thread_to_insert->current_priority < thread_next->current_priority;
>> +}
>> +
>> +RTEMS_INLINE_ROUTINE void _Scheduler_simple_Insert_as_first(
>> +  Chain_Control *chain,
>> +  Thread_Control *to_insert
>> +)
>> +{
>> +  _Chain_Insert_ordered_unprotected(
>> +    chain,
>> +    &to_insert->Object.Node,
>> +    _Scheduler_simple_Insert_as_first_order
>> +  );
>> +}
>> +
>> +RTEMS_INLINE_ROUTINE void _Scheduler_simple_Insert_as_last(
>> +  Chain_Control *chain,
>> +  Thread_Control *to_insert
>> +)
>> +{
>> +  _Chain_Insert_ordered_unprotected(
>> +    chain,
>> +    &to_insert->Object.Node,
>> +    _Scheduler_simple_Insert_as_last_order
>> +  );
>> +}
> For these functions _Scheduler_simple_Insert_as_first() and
> _Scheduler_simple_Insert_as_last() the name means they break priority
> ties by FIFO and LIFO semantics? Before I read the code, I thought it
> meant break ties by inserting to the first or last position of ties,
> which is the opposite. I would prefer to have
> _Scheduler_simple_Insert_as_fifo()/lifo() instead for added clarity.
>
I guess saying fifo/lifo could be confusing also, since the insert is
not fifo/lifo, just how priority ties are broken. So maybe
_Scheduler_simple_Insert_priority_fifo()/lifo()?