Strong APA Scheduler : First Draft

[Sebastian Huber]

On 27/07/2020 09:44, Richi Dubey wrote:

>     Which compiler error do you get? Maybe there is a cyclic dependency.
>
> I assumed that the schedulersmp.h already includes the percpu.h which 
> was not the case. My bad. The error has been removed.
>
> I assumed this because schedulersmp.h uses 
> <https://git.rtems.org/rtems/tree/cpukit/include/rtems/score/schedulersmp.h?id=3a95a07d88a6926bd2f67dc53c977b8dbc828f9c#n127> Per_CPU_Control 
> and does not show any compilation error, so it should have the 
> percpu.h included in one of its included header files right? If it 
> has, why did my schedulerstrongapa.h that had the schedulersmp.h 
> included give the following error:
>
> /home/richi/quick-start/src/rtems/cpukit/include/rtems/score/schedulerstrongapa.h:102:3: 
> error: unknown type name 'Per_CPU_Control'
>    Per_CPU_Control cpu;

We have two kinds of header files in the implementation of RTEMS. 
Firstly, some header files are included in API header files and are thus 
visible to application code. These header files should only define 
things which are strictly necessary for applications. Secondly, some 
header files are only included in implementation source files.

The purpose of <rtems/score/schedulerstrongapa.h> is to enable the 
application to configure this scheduler and nothing more. Please note 
that <rtems/score/scheduler.h> uses

struct Per_CPU_Control  *cpu

and NOT

Per_CPU_Control  *cpu

You can use struct Per_CPU_Control with a forward declaration. This 
enables the use of this header file without having to include 
<rtems/score/percpu.h>. You should not include <rtems/score/percpu.h> in 
<rtems/score/schedulerstrongapa.h> and remove everything from this file 
which is not necessary to configure the scheduler.