forked from Imagelibrary/rtems
b8a5abf3fa
Previously, the _Thread_Heir was updated unconditionally in case a new heir was determined. The _Thread_Dispatch_necessary was only updated in case the executing thread was preemptible or an internal thread was unblocked. Change this to update the _Thread_Heir and _Thread_Dispatch_necessary only in case the currently selected heir thread is preemptible or a dispatch is forced. Move the schedule decision into the change priority operation and use the schedule operation only in rtems_task_mode() in case preemption is enabled or an ASR dispatch is necessary. This is a behaviour change. Previously, the RTEMS_NO_PREEMPT also prevented signal delivery in certain cases (not always). Now, signal delivery is no longer influenced by RTEMS_NO_PREEMPT. Since the currently selected heir thread is used to determine if a new heir is chosen, non-preemptible heir threads currently not executing now prevent a new heir. This may have an application impact, see change test tm04. Document this change in sp04. Update #2273.