score: Add thread priority to scheduler nodes

The thread priority is manifest in two independent areas.  One area is
the user visible thread priority along with a potential thread queue.
The other is the scheduler.  Currently, a thread priority update via
_Thread_Change_priority() first updates the user visble thread priority
and the thread queue, then the scheduler is notified if necessary.  The
priority is passed to the scheduler via a local variable.  A generation
counter ensures that the scheduler discards out-of-date priorities.

This use of a local variable ties the update in these two areas close
together.  For later enhancements and the OMIP locking protocol
implementation we need more flexibility.  Add a thread priority
information block to Scheduler_Node and synchronize priority value
updates via a sequence lock on SMP configurations.

Update #2556.

1 files changed, 3 insertions, 6 deletions

diff --git a/cpukit/score/include/rtems/score/schedulersimple.h b/cpukit/score/include/rtems/score/schedulersimple.h
index 00f8dd790f..3fa4b333f9 100644
--- a/cpukit/score/include/rtems/score/schedulersimple.h
+++ b/cpukit/score/include/rtems/score/schedulersimple.h
@@ -44,13 +44,12 @@ extern "C" {
     _Scheduler_simple_Yield,              /* yield entry point */ \
     _Scheduler_simple_Block,              /* block entry point */ \
     _Scheduler_simple_Unblock,            /* unblock entry point */ \
-    _Scheduler_simple_Change_priority,    /* change priority entry point */ \
+    _Scheduler_simple_Update_priority,    /* update priority entry point */ \
     _Scheduler_default_Map_priority,      /* map priority entry point */ \
     _Scheduler_default_Unmap_priority,    /* unmap priority entry point */ \
     SCHEDULER_OPERATION_DEFAULT_ASK_FOR_HELP \
     _Scheduler_default_Node_initialize,   /* node initialize entry point */ \
     _Scheduler_default_Node_destroy,      /* node destroy entry point */ \
-    _Scheduler_default_Update_priority,   /* update priority entry point */ \
     _Scheduler_default_Release_job,       /* new period of task */ \
     _Scheduler_default_Tick,              /* tick entry point */ \
     _Scheduler_default_Start_idle         /* start idle entry point */ \
@@ -145,11 +144,9 @@ Scheduler_Void_or_thread _Scheduler_simple_Unblock(
   Thread_Control          *the_thread
 );
 
-Scheduler_Void_or_thread _Scheduler_simple_Change_priority(
+Scheduler_Void_or_thread _Scheduler_simple_Update_priority(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread,
-  Priority_Control         new_priority,
-  bool                     prepend_it
+  Thread_Control          *the_thread
 );
 
 /**@}*/