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counter ensures that the scheduler discards out-of-date priorities.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, 5 insertions, 13 deletions

diff --git a/cpukit/score/include/rtems/score/schedulerstrongapa.h b/cpukit/score/include/rtems/score/schedulerstrongapa.h
index d7c3888d5a..e2a33afed7 100644
--- a/cpukit/score/include/rtems/score/schedulerstrongapa.h
+++ b/cpukit/score/include/rtems/score/schedulerstrongapa.h
@@ -83,13 +83,12 @@ typedef struct {
     _Scheduler_strong_APA_Yield, \
     _Scheduler_strong_APA_Block, \
     _Scheduler_strong_APA_Unblock, \
-    _Scheduler_strong_APA_Change_priority, \
+    _Scheduler_strong_APA_Update_priority, \
     _Scheduler_default_Map_priority, \
     _Scheduler_default_Unmap_priority, \
     _Scheduler_strong_APA_Ask_for_help, \
     _Scheduler_strong_APA_Node_initialize, \
     _Scheduler_default_Node_destroy, \
-    _Scheduler_strong_APA_Update_priority, \
     _Scheduler_default_Release_job, \
     _Scheduler_default_Tick, \
     _Scheduler_SMP_Start_idle \
@@ -100,7 +99,8 @@ void _Scheduler_strong_APA_Initialize( const Scheduler_Control *scheduler );
 
 void _Scheduler_strong_APA_Node_initialize(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
+  Thread_Control          *the_thread,
+  Priority_Control         priority
 );
 
 void _Scheduler_strong_APA_Block(
@@ -113,11 +113,9 @@ Thread_Control *_Scheduler_strong_APA_Unblock(
   Thread_Control          *the_thread
 );
 
-Thread_Control *_Scheduler_strong_APA_Change_priority(
+Thread_Control *_Scheduler_strong_APA_Update_priority(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread,
-  Priority_Control         new_priority,
-  bool                     prepend_it
+  Thread_Control          *the_thread
 );
 
 Thread_Control *_Scheduler_strong_APA_Ask_for_help(
@@ -126,12 +124,6 @@ Thread_Control *_Scheduler_strong_APA_Ask_for_help(
   Thread_Control          *offers_help
 );
 
-void _Scheduler_strong_APA_Update_priority(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread,
-  Priority_Control         new_priority
-);
-
 Thread_Control *_Scheduler_strong_APA_Yield(
   const Scheduler_Control *scheduler,
   Thread_Control          *the_thread