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counter ensures that the scheduler discards out-of-date priorities.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, 7 insertions, 21 deletions

diff --git a/cpukit/score/src/schedulersimplesmp.c b/cpukit/score/src/schedulersimplesmp.c
index 0f05a7da81..f368ead556 100644
--- a/cpukit/score/src/schedulersimplesmp.c
+++ b/cpukit/score/src/schedulersimplesmp.c
@@ -44,12 +44,13 @@ void _Scheduler_simple_SMP_Initialize( const Scheduler_Control *scheduler )
 
 void _Scheduler_simple_SMP_Node_initialize(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
+  Thread_Control          *the_thread,
+  Priority_Control         priority
 )
 {
   Scheduler_SMP_Node *node = _Scheduler_SMP_Thread_get_own_node( the_thread );
 
-  _Scheduler_SMP_Node_initialize( node, the_thread );
+  _Scheduler_SMP_Node_initialize( node, the_thread, priority );
 }
 
 static void _Scheduler_simple_SMP_Do_update(
@@ -65,18 +66,6 @@ static void _Scheduler_simple_SMP_Do_update(
   _Scheduler_SMP_Node_update_priority( node, new_priority );
 }
 
-void _Scheduler_simple_SMP_Update_priority(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *thread,
-  Priority_Control         new_priority
-)
-{
-  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
-  Scheduler_Node *node = _Scheduler_Thread_get_node( thread );
-
-  _Scheduler_simple_SMP_Do_update( context, node, new_priority );
-}
-
 static Scheduler_Node *_Scheduler_simple_SMP_Get_highest_ready(
   Scheduler_Context *context,
   Scheduler_Node    *node
@@ -295,24 +284,21 @@ Thread_Control *_Scheduler_simple_SMP_Unblock(
   return _Scheduler_SMP_Unblock(
     context,
     thread,
+    _Scheduler_simple_SMP_Do_update,
     _Scheduler_simple_SMP_Enqueue_fifo
   );
 }
 
-Thread_Control *_Scheduler_simple_SMP_Change_priority(
+Thread_Control *_Scheduler_simple_SMP_Update_priority(
   const Scheduler_Control *scheduler,
-  Thread_Control          *thread,
-  Priority_Control         new_priority,
-  bool                     prepend_it
+  Thread_Control          *thread
 )
 {
   Scheduler_Context *context = _Scheduler_Get_context( scheduler );
 
-  return _Scheduler_SMP_Change_priority(
+  return _Scheduler_SMP_Update_priority(
     context,
     thread,
-    new_priority,
-    prepend_it,
     _Scheduler_simple_SMP_Extract_from_ready,
     _Scheduler_simple_SMP_Do_update,
     _Scheduler_simple_SMP_Enqueue_fifo,