Need help in understanding some of the existing code in RTEMS

[Sebastian Huber]

On 13/07/2020 13:27, Richi Dubey wrote:

> We use a zero-length array 
> <https://git.rtems.org/rtems/tree/cpukit/include/rtems/score/scheduleredfsmp.h#n105> in 
> the definition of Scheduler_EDF_SMP_Context, but I can not see any 
> code in scheduleredfsmp.c 
> (https://git.rtems.org/rtems/tree/cpukit/score/src/scheduleredfsmp.c) 
> which actually increases the size of the array. All I can see is code 
> that access/manipulate the array elements, but I do not see any code 
> which does malloc/adds Scheduler_EDF_SMP_Ready_queue elements to the 
> array.

It was difficult to find this mail. Descriptive subjects would be helpful.

This is a good question and I think we really have to improve our 
internal documentation. In Doxygen there is no good link from internal 
objects to their definition through application configuration options. 
Having the application configuration options in Doxygen would be 
definitely help here:

https://lists.rtems.org/pipermail/devel/2020-July/060496.html

The scheduler contexts and controls are generated by the confdefs.h 
related header files. Please have a look at:

https://git.rtems.org/rtems/tree/cpukit/include/rtems/confdefs/scheduler.h

Here are important scheduler-specific macros:

https://git.rtems.org/rtems/tree/cpukit/include/rtems/scheduler.h#n131