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counter ensures that the scheduler discards out-of-date priorities.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.

20 files changed, 181 insertions, 250 deletions

diff --git a/cpukit/score/src/schedulercbsnodeinit.c b/cpukit/score/src/schedulercbsnodeinit.c
index df679b6588..3aa825bd12 100644
--- a/cpukit/score/src/schedulercbsnodeinit.c
+++ b/cpukit/score/src/schedulercbsnodeinit.c
@@ -22,12 +22,13 @@
 
 void _Scheduler_CBS_Node_initialize(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
+  Thread_Control          *the_thread,
+  Priority_Control         priority
 )
 {
   Scheduler_CBS_Node *node;
 
-  _Scheduler_EDF_Node_initialize( scheduler, the_thread );
+  _Scheduler_EDF_Node_initialize( scheduler, the_thread, priority );
 
   node = _Scheduler_CBS_Thread_get_node( the_thread );
   node->cbs_server = NULL;
diff --git a/cpukit/score/src/schedulercbsunblock.c b/cpukit/score/src/schedulercbsunblock.c
index 3f5bd33623..70db651080 100644
--- a/cpukit/score/src/schedulercbsunblock.c
+++ b/cpukit/score/src/schedulercbsunblock.c
@@ -34,11 +34,13 @@ Scheduler_Void_or_thread _Scheduler_CBS_Unblock(
   Scheduler_CBS_Node    *node;
   Scheduler_CBS_Server  *serv_info;
   Priority_Control       priority;
+  bool                   prepend_it;
 
   context = _Scheduler_EDF_Get_context( scheduler );
   node = _Scheduler_CBS_Thread_get_node( the_thread );
   serv_info = node->cbs_server;
-  priority = node->Base.current_priority;
+  priority = _Scheduler_Node_get_priority( &node->Base.Base, &prepend_it );
+  (void) prepend_it;
 
   /*
    * Late unblock rule for deadline-driven tasks. The remaining time to
diff --git a/cpukit/score/src/schedulerdefaultnodeinit.c b/cpukit/score/src/schedulerdefaultnodeinit.c
index a96a528ee4..de2b6c8dd3 100644
--- a/cpukit/score/src/schedulerdefaultnodeinit.c
+++ b/cpukit/score/src/schedulerdefaultnodeinit.c
@@ -23,12 +23,13 @@
 
 void _Scheduler_default_Node_initialize(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
+  Thread_Control          *the_thread,
+  Priority_Control         priority
 )
 {
   Scheduler_Node *node = _Scheduler_Thread_get_own_node( the_thread );
 
   (void) scheduler;
 
-  _Scheduler_Node_do_initialize( node, the_thread );
+  _Scheduler_Node_do_initialize( node, the_thread, priority );
 }
diff --git a/cpukit/score/src/schedulerdefaultupdate.c b/cpukit/score/src/schedulerdefaultupdate.c
deleted file mode 100644
index fcdc838502..0000000000
--- a/cpukit/score/src/schedulerdefaultupdate.c
+++ /dev/null
@@ -1,33 +0,0 @@
-/**
- * @file
- *
- * @brief Scheduler Default Update Operation
- *
- * @ingroup ScoreScheduler
- */
-
-/*
- *  COPYRIGHT (c) 2011.
- *  On-Line Applications Research Corporation (OAR).
- *
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <rtems/score/scheduler.h>
-
-void _Scheduler_default_Update_priority(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread,
-  Priority_Control         new_priority
-)
-{
-  (void) scheduler;
-  (void) the_thread;
-  (void) new_priority;
-}
diff --git a/cpukit/score/src/scheduleredfchangepriority.c b/cpukit/score/src/scheduleredfchangepriority.c
index a0f5ec7061..9a73128e4c 100644
--- a/cpukit/score/src/scheduleredfchangepriority.c
+++ b/cpukit/score/src/scheduleredfchangepriority.c
@@ -36,31 +36,42 @@ Priority_Control _Scheduler_EDF_Unmap_priority(
   return priority & ~SCHEDULER_EDF_PRIO_MSB;
 }
 
-Scheduler_Void_or_thread _Scheduler_EDF_Change_priority(
+Scheduler_Void_or_thread _Scheduler_EDF_Update_priority(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread,
-  Priority_Control         new_priority,
-  bool                     prepend_it
+  Thread_Control          *the_thread
 )
 {
   Scheduler_EDF_Context *context;
   Scheduler_EDF_Node    *node;
+  Priority_Control       priority;
+  bool                   prepend_it;
+
+  if ( !_Thread_Is_ready( the_thread ) ) {
+    /* Nothing to do */
+    SCHEDULER_RETURN_VOID_OR_NULL;
+  }
 
-  context = _Scheduler_EDF_Get_context( scheduler );
   node = _Scheduler_EDF_Thread_get_node( the_thread );
+  priority = _Scheduler_Node_get_priority( &node->Base, &prepend_it );
 
-  if ( ( new_priority & SCHEDULER_EDF_PRIO_MSB ) != 0 ) {
-    node->background_priority = new_priority;
+  if ( priority == node->current_priority ) {
+    /* Nothing to do */
+    SCHEDULER_RETURN_VOID_OR_NULL;
   }
 
-  node->current_priority = new_priority;
+  if ( ( priority & SCHEDULER_EDF_PRIO_MSB ) != 0 ) {
+    node->background_priority = priority;
+  }
+
+  node->current_priority = priority;
+  context = _Scheduler_EDF_Get_context( scheduler );
 
   _Scheduler_EDF_Extract( context, node );
 
   if ( prepend_it ) {
-    _Scheduler_EDF_Enqueue_first( context, node, new_priority );
+    _Scheduler_EDF_Enqueue_first( context, node, priority );
   } else {
-    _Scheduler_EDF_Enqueue( context, node, new_priority );
+    _Scheduler_EDF_Enqueue( context, node, priority );
   }
 
   _Scheduler_EDF_Schedule_body( scheduler, the_thread, false );
diff --git a/cpukit/score/src/scheduleredfnodeinit.c b/cpukit/score/src/scheduleredfnodeinit.c
index ec6d9bae7c..6005fa0538 100644
--- a/cpukit/score/src/scheduleredfnodeinit.c
+++ b/cpukit/score/src/scheduleredfnodeinit.c
@@ -22,14 +22,15 @@
 
 void _Scheduler_EDF_Node_initialize(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
+  Thread_Control          *the_thread,
+  Priority_Control         priority
 )
 {
   Scheduler_EDF_Node *node = _Scheduler_EDF_Thread_get_node( the_thread );
 
   (void) scheduler;
 
-  _Scheduler_Node_do_initialize( &node->Base, the_thread );
+  _Scheduler_Node_do_initialize( &node->Base, the_thread, priority );
 
   node->thread = the_thread;
 }
diff --git a/cpukit/score/src/scheduleredfunblock.c b/cpukit/score/src/scheduleredfunblock.c
index b3acbcd4c2..9f80fa9aea 100644
--- a/cpukit/score/src/scheduleredfunblock.c
+++ b/cpukit/score/src/scheduleredfunblock.c
@@ -29,11 +29,16 @@ Scheduler_Void_or_thread _Scheduler_EDF_Unblock(
 {
   Scheduler_EDF_Context *context;
   Scheduler_EDF_Node    *node;
+  Priority_Control       priority;
+  bool                   prepend_it;
 
   context = _Scheduler_EDF_Get_context( scheduler );
   node = _Scheduler_EDF_Thread_get_node( the_thread );
+  priority = _Scheduler_Node_get_priority( &node->Base, &prepend_it );
+  (void) prepend_it;
 
-  _Scheduler_EDF_Enqueue( context, node, node->current_priority );
+  node->current_priority = priority;
+  _Scheduler_EDF_Enqueue( context, node, priority );
 
   /*
    *  If the thread that was unblocked is more important than the heir,
@@ -47,11 +52,8 @@ Scheduler_Void_or_thread _Scheduler_EDF_Unblock(
    *    Even if the thread isn't preemptible, if the new heir is
    *    a pseudo-ISR system task, we need to do a context switch.
    */
-  if ( the_thread->current_priority < _Thread_Heir->current_priority ) {
-    _Scheduler_Update_heir(
-      the_thread,
-      the_thread->current_priority == PRIORITY_PSEUDO_ISR
-    );
+  if ( priority < _Thread_Heir->current_priority ) {
+    _Scheduler_Update_heir( the_thread, priority == PRIORITY_PSEUDO_ISR );
   }
 
   SCHEDULER_RETURN_VOID_OR_NULL;
diff --git a/cpukit/score/src/scheduleredfupdate.c b/cpukit/score/src/scheduleredfupdate.c
deleted file mode 100644
index 5d475fe5f1..0000000000
--- a/cpukit/score/src/scheduleredfupdate.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/**
- *  @file
- *
- *  @brief Scheduler EDF Update
- *  @ingroup ScoreScheduler
- */
-
-/*
- *  Copyright (C) 2011 Petr Benes.
- *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
- *
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <rtems/score/scheduleredfimpl.h>
-
-void _Scheduler_EDF_Update_priority(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread,
-  Priority_Control         new_priority
-)
-{
-  Scheduler_EDF_Node *node;
-
-  node = _Scheduler_EDF_Thread_get_node( the_thread );
-
-  if ( ( new_priority & SCHEDULER_EDF_PRIO_MSB ) != 0 ) {
-    node->background_priority = new_priority;
-  }
-
-  node->current_priority = new_priority;
-}
diff --git a/cpukit/score/src/schedulerpriority.c b/cpukit/score/src/schedulerpriority.c
index 61505a4fce..2719697ba3 100644
--- a/cpukit/score/src/schedulerpriority.c
+++ b/cpukit/score/src/schedulerpriority.c
@@ -32,3 +32,24 @@ void _Scheduler_priority_Initialize( const Scheduler_Control *scheduler )
     scheduler->maximum_priority
   );
 }
+
+void _Scheduler_priority_Node_initialize(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Priority_Control         priority
+)
+{
+  Scheduler_priority_Context *context;
+  Scheduler_priority_Node    *node;
+
+  context = _Scheduler_priority_Get_context( scheduler );
+  node = _Scheduler_priority_Thread_get_node( the_thread );
+
+  _Scheduler_Node_do_initialize( &node->Base, the_thread, priority );
+  _Scheduler_priority_Ready_queue_update(
+    &node->Ready_queue,
+    priority,
+    &context->Bit_map,
+    &context->Ready[ 0 ]
+  );
+}
diff --git a/cpukit/score/src/schedulerpriorityaffinitysmp.c b/cpukit/score/src/schedulerpriorityaffinitysmp.c
index fa56e2b1b5..3618f4c901 100644
--- a/cpukit/score/src/schedulerpriorityaffinitysmp.c
+++ b/cpukit/score/src/schedulerpriorityaffinitysmp.c
@@ -96,15 +96,14 @@ _Scheduler_priority_affinity_SMP_Node_downcast(
  */
 void _Scheduler_priority_affinity_SMP_Node_initialize(
   const Scheduler_Control *scheduler,
-  Thread_Control          *thread
+  Thread_Control          *the_thread,
+  Priority_Control         priority
 )
 {
   Scheduler_priority_affinity_SMP_Node *node =
-    _Scheduler_priority_affinity_SMP_Thread_get_own_node( thread );
-
-  (void) scheduler;
+    _Scheduler_priority_affinity_SMP_Thread_get_own_node( the_thread );
 
-  _Scheduler_SMP_Node_initialize( &node->Base.Base, thread );
+  _Scheduler_priority_SMP_Node_initialize( scheduler, the_thread, priority );
 
   /*
    *  All we add is affinity information to the basic SMP node.
@@ -409,6 +408,7 @@ Thread_Control *_Scheduler_priority_affinity_SMP_Unblock(
   needs_help = _Scheduler_SMP_Unblock(
     context,
     thread,
+    _Scheduler_priority_SMP_Do_update,
     _Scheduler_priority_affinity_SMP_Enqueue_fifo
   );
 
@@ -535,21 +535,17 @@ static Thread_Control *_Scheduler_priority_affinity_SMP_Enqueue_scheduled_fifo(
 /*
  * This is the public scheduler specific Change Priority operation.
  */
-Thread_Control *_Scheduler_priority_affinity_SMP_Change_priority(
+Thread_Control *_Scheduler_priority_affinity_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 );
   Thread_Control    *displaced;
 
-  displaced = _Scheduler_SMP_Change_priority(
+  displaced = _Scheduler_SMP_Update_priority(
     context,
     thread,
-    new_priority,
-    prepend_it,
     _Scheduler_priority_SMP_Extract_from_ready,
     _Scheduler_priority_SMP_Do_update,
     _Scheduler_priority_affinity_SMP_Enqueue_fifo,
diff --git a/cpukit/score/src/schedulerprioritychangepriority.c b/cpukit/score/src/schedulerprioritychangepriority.c
index f883e02d43..04599f5c74 100644
--- a/cpukit/score/src/schedulerprioritychangepriority.c
+++ b/cpukit/score/src/schedulerprioritychangepriority.c
@@ -21,16 +21,30 @@
 
 #include <rtems/score/schedulerpriorityimpl.h>
 
-Scheduler_Void_or_thread _Scheduler_priority_Change_priority(
+Scheduler_Void_or_thread _Scheduler_priority_Update_priority(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread,
-  Priority_Control         new_priority,
-  bool                     prepend_it
+  Thread_Control          *the_thread
 )
 {
-  Scheduler_priority_Context *context =
-    _Scheduler_priority_Get_context( scheduler );
-  Scheduler_priority_Node *node = _Scheduler_priority_Thread_get_node( the_thread );
+  Scheduler_priority_Context *context;
+  Scheduler_priority_Node    *node;
+  unsigned int                priority;
+  bool                        prepend_it;
+
+  if ( !_Thread_Is_ready( the_thread ) ) {
+    /* Nothing to do */
+    SCHEDULER_RETURN_VOID_OR_NULL;
+  }
+
+  node = _Scheduler_priority_Thread_get_node( the_thread );
+  priority = _Scheduler_Node_get_priority( &node->Base, &prepend_it );
+
+  if ( priority == node->Ready_queue.current_priority ) {
+    /* Nothing to do */
+    SCHEDULER_RETURN_VOID_OR_NULL;
+  }
+
+  context = _Scheduler_priority_Get_context( scheduler );
 
   _Scheduler_priority_Ready_queue_extract(
     &the_thread->Object.Node,
@@ -40,7 +54,7 @@ Scheduler_Void_or_thread _Scheduler_priority_Change_priority(
 
   _Scheduler_priority_Ready_queue_update(
     &node->Ready_queue,
-    new_priority,
+    priority,
     &context->Bit_map,
     &context->Ready[ 0 ]
   );
diff --git a/cpukit/score/src/schedulerprioritysmp.c b/cpukit/score/src/schedulerprioritysmp.c
index bd042d2534..aba863e66a 100644
--- a/cpukit/score/src/schedulerprioritysmp.c
+++ b/cpukit/score/src/schedulerprioritysmp.c
@@ -47,24 +47,27 @@ void _Scheduler_priority_SMP_Initialize( const Scheduler_Control *scheduler )
 
 void _Scheduler_priority_SMP_Node_initialize(
   const Scheduler_Control *scheduler,
-  Thread_Control *thread
+  Thread_Control          *the_thread,
+  Priority_Control         priority
 )
 {
-  Scheduler_SMP_Node *node = _Scheduler_SMP_Thread_get_own_node( thread );
-
-  _Scheduler_SMP_Node_initialize( node, thread );
-}
+  Scheduler_Context              *context;
+  Scheduler_priority_SMP_Context *self;
+  Scheduler_priority_SMP_Node    *node;
 
-void _Scheduler_priority_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 );
+  context = _Scheduler_Get_context( scheduler );
+  self = _Scheduler_priority_SMP_Get_self( context );
+  node = _Scheduler_priority_SMP_Node_downcast(
+    _Scheduler_Thread_get_own_node( the_thread )
+  );
 
-  _Scheduler_priority_SMP_Do_update( context, node, new_priority );
+  _Scheduler_SMP_Node_initialize( &node->Base, the_thread, priority );
+  _Scheduler_priority_Ready_queue_update(
+    &node->Ready_queue,
+    priority,
+    &self->Bit_map,
+    &self->Ready[ 0 ]
+  );
 }
 
 static Scheduler_Node *_Scheduler_priority_SMP_Get_highest_ready(
@@ -213,24 +216,21 @@ Thread_Control *_Scheduler_priority_SMP_Unblock(
   return _Scheduler_SMP_Unblock(
     context,
     thread,
+    _Scheduler_priority_SMP_Do_update,
     _Scheduler_priority_SMP_Enqueue_fifo
   );
 }
 
-Thread_Control *_Scheduler_priority_SMP_Change_priority(
+Thread_Control *_Scheduler_priority_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_priority_SMP_Extract_from_ready,
     _Scheduler_priority_SMP_Do_update,
     _Scheduler_priority_SMP_Enqueue_fifo,
diff --git a/cpukit/score/src/schedulerpriorityunblock.c b/cpukit/score/src/schedulerpriorityunblock.c
index a912ebfbe2..ba8501bc50 100644
--- a/cpukit/score/src/schedulerpriorityunblock.c
+++ b/cpukit/score/src/schedulerpriorityunblock.c
@@ -27,9 +27,24 @@ Scheduler_Void_or_thread _Scheduler_priority_Unblock (
   Thread_Control          *the_thread
 )
 {
-  Scheduler_priority_Context *context =
-    _Scheduler_priority_Get_context( scheduler );
-  Scheduler_priority_Node *node = _Scheduler_priority_Thread_get_node( the_thread );
+  Scheduler_priority_Context *context;
+  Scheduler_priority_Node    *node;
+  unsigned int                priority;
+  bool                        prepend_it;
+
+  context = _Scheduler_priority_Get_context( scheduler );
+  node = _Scheduler_priority_Thread_get_node( the_thread );
+  priority = _Scheduler_Node_get_priority( &node->Base, &prepend_it );
+  (void) prepend_it;
+
+  if ( priority != node->Ready_queue.current_priority ) {
+    _Scheduler_priority_Ready_queue_update(
+      &node->Ready_queue,
+      priority,
+      &context->Bit_map,
+      &context->Ready[ 0 ]
+    );
+  }
 
   _Scheduler_priority_Ready_queue_enqueue(
     &the_thread->Object.Node,
@@ -51,11 +66,8 @@ Scheduler_Void_or_thread _Scheduler_priority_Unblock (
    *    Even if the thread isn't preemptible, if the new heir is
    *    a pseudo-ISR system task, we need to do a context switch.
    */
-  if ( the_thread->current_priority < _Thread_Heir->current_priority ) {
-    _Scheduler_Update_heir(
-      the_thread,
-      the_thread->current_priority == PRIORITY_PSEUDO_ISR
-    );
+  if ( priority < _Thread_Heir->current_priority ) {
+    _Scheduler_Update_heir( the_thread, priority == PRIORITY_PSEUDO_ISR );
   }
 
   SCHEDULER_RETURN_VOID_OR_NULL;
diff --git a/cpukit/score/src/schedulerpriorityupdate.c b/cpukit/score/src/schedulerpriorityupdate.c
deleted file mode 100644
index d2a7e6ccba..0000000000
--- a/cpukit/score/src/schedulerpriorityupdate.c
+++ /dev/null
@@ -1,39 +0,0 @@
-/**
- * @file
- *
- * @brief Update Scheduler Priority 
- * @ingroup ScoreScheduler
- */
-
-/*
- *  Copyright (C) 2010 Gedare Bloom.
- *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
- *
- *  The license and distribution terms for this file may be
- *  found in the file LICENSE in this distribution or at
- *  http://www.rtems.org/license/LICENSE.
- */
-
-#if HAVE_CONFIG_H
-#include "config.h"
-#endif
-
-#include <rtems/score/schedulerpriorityimpl.h>
-
-void _Scheduler_priority_Update_priority(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread,
-  Priority_Control         new_priority
-)
-{
-  Scheduler_priority_Context *context =
-    _Scheduler_priority_Get_context( scheduler );
-  Scheduler_priority_Node *node = _Scheduler_priority_Thread_get_node( the_thread );
-
-  _Scheduler_priority_Ready_queue_update(
-    &node->Ready_queue,
-    new_priority,
-    &context->Bit_map,
-    &context->Ready[ 0 ]
-  );
-}
diff --git a/cpukit/score/src/schedulersimplechangepriority.c b/cpukit/score/src/schedulersimplechangepriority.c
index 9b94b3ab26..9d4a565dbd 100644
--- a/cpukit/score/src/schedulersimplechangepriority.c
+++ b/cpukit/score/src/schedulersimplechangepriority.c
@@ -21,15 +21,23 @@
 
 #include <rtems/score/schedulersimpleimpl.h>
 
-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
 )
 {
-  Scheduler_simple_Context *context =
-    _Scheduler_simple_Get_context( scheduler );
+  Scheduler_simple_Context *context;
+  Scheduler_Node           *node;
+  bool                      prepend_it;
+
+  if ( !_Thread_Is_ready( the_thread ) ) {
+    /* Nothing to do */
+    SCHEDULER_RETURN_VOID_OR_NULL;
+  }
+
+  context = _Scheduler_simple_Get_context( scheduler );
+  node = _Scheduler_Thread_get_node( the_thread );
+  _Scheduler_Node_get_priority( node, &prepend_it );
 
   _Scheduler_simple_Extract( scheduler, the_thread );
 
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,
diff --git a/cpukit/score/src/schedulerstrongapa.c b/cpukit/score/src/schedulerstrongapa.c
index dd4409766e..51dac679ed 100644
--- a/cpukit/score/src/schedulerstrongapa.c
+++ b/cpukit/score/src/schedulerstrongapa.c
@@ -173,24 +173,27 @@ void _Scheduler_strong_APA_Initialize( const Scheduler_Control *scheduler )
 
 void _Scheduler_strong_APA_Node_initialize(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  Scheduler_SMP_Node *node = _Scheduler_SMP_Thread_get_own_node( the_thread );
-
-  _Scheduler_SMP_Node_initialize( node, the_thread );
-}
-
-void _Scheduler_strong_APA_Update_priority(
-  const Scheduler_Control *scheduler,
   Thread_Control          *the_thread,
-  Priority_Control         new_priority
+  Priority_Control         priority
 )
 {
-  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
-  Scheduler_Node *node = _Scheduler_Thread_get_node( the_thread );
+  Scheduler_Context            *context;
+  Scheduler_strong_APA_Context *self;
+  Scheduler_strong_APA_Node    *node;
+
+  context = _Scheduler_Get_context( scheduler );
+  self = _Scheduler_strong_APA_Get_self( context );
+  node = _Scheduler_strong_APA_Node_downcast(
+    _Scheduler_Thread_get_own_node( the_thread )
+  );
 
-  _Scheduler_strong_APA_Do_update( context, node, new_priority );
+  _Scheduler_SMP_Node_initialize( &node->Base, the_thread, priority );
+  _Scheduler_priority_Ready_queue_update(
+    &node->Ready_queue,
+    priority,
+    &self->Bit_map,
+    &self->Ready[ 0 ]
+  );
 }
 
 static Scheduler_Node *_Scheduler_strong_APA_Get_highest_ready(
@@ -339,24 +342,21 @@ Thread_Control *_Scheduler_strong_APA_Unblock(
   return _Scheduler_SMP_Unblock(
     context,
     the_thread,
+    _Scheduler_strong_APA_Do_update,
     _Scheduler_strong_APA_Enqueue_fifo
   );
 }
 
-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
 )
 {
   Scheduler_Context *context = _Scheduler_Get_context( scheduler );
 
-  return _Scheduler_SMP_Change_priority(
+  return _Scheduler_SMP_Update_priority(
     context,
     the_thread,
-    new_priority,
-    prepend_it,
     _Scheduler_strong_APA_Extract_from_ready,
     _Scheduler_strong_APA_Do_update,
     _Scheduler_strong_APA_Enqueue_fifo,
diff --git a/cpukit/score/src/thread.c b/cpukit/score/src/thread.c
index 2e0bbd91bb..8028540e10 100644
--- a/cpukit/score/src/thread.c
+++ b/cpukit/score/src/thread.c
@@ -34,7 +34,6 @@ THREAD_OFFSET_ASSERT( Join_queue );
 THREAD_OFFSET_ASSERT( current_state );
 THREAD_OFFSET_ASSERT( current_priority );
 THREAD_OFFSET_ASSERT( real_priority );
-THREAD_OFFSET_ASSERT( priority_generation );
 THREAD_OFFSET_ASSERT( priority_restore_hint );
 THREAD_OFFSET_ASSERT( resource_count );
 THREAD_OFFSET_ASSERT( Wait );
diff --git a/cpukit/score/src/threadchangepriority.c b/cpukit/score/src/threadchangepriority.c
index 152646f52f..7b22371326 100644
--- a/cpukit/score/src/threadchangepriority.c
+++ b/cpukit/score/src/threadchangepriority.c
@@ -50,11 +50,12 @@ void _Thread_Change_priority(
    *  we are not REALLY changing priority.
    */
   if ( ( *filter )( the_thread, &new_priority, arg ) ) {
-    uint32_t my_generation;
+    Scheduler_Node *own_node;
+
+    own_node = _Scheduler_Thread_get_own_node( the_thread );
+    _Scheduler_Node_set_priority( own_node, new_priority, prepend_it );
 
-    my_generation = the_thread->priority_generation + 1;
     the_thread->current_priority = new_priority;
-    the_thread->priority_generation = my_generation;
 
     ( *the_thread->Wait.operations->priority_change )(
       the_thread,
@@ -65,19 +66,7 @@ void _Thread_Change_priority(
     _Thread_Lock_release( lock, &lock_context );
 
     _Thread_State_acquire( the_thread, &lock_context );
-
-    if ( the_thread->priority_generation == my_generation ) {
-      if ( _States_Is_ready( the_thread->current_state ) ) {
-        _Scheduler_Change_priority(
-          the_thread,
-          new_priority,
-          prepend_it
-        );
-      } else {
-        _Scheduler_Update_priority( the_thread, new_priority );
-      }
-    }
-
+    _Scheduler_Update_priority( the_thread );
     _Thread_State_release( the_thread, &lock_context );
   } else {
     _Thread_Lock_release( lock, &lock_context );
diff --git a/cpukit/score/src/threadinitialize.c b/cpukit/score/src/threadinitialize.c
index 229d68bf74..10dbf02dfc 100644
--- a/cpukit/score/src/threadinitialize.c
+++ b/cpukit/score/src/threadinitialize.c
@@ -200,11 +200,9 @@ bool _Thread_Initialize(
 
   RTEMS_STATIC_ASSERT( THREAD_WAIT_FLAGS_INITIAL == 0, Wait_flags );
 
-  _Scheduler_Node_initialize( scheduler, the_thread );
+  _Scheduler_Node_initialize( scheduler, the_thread, priority );
   scheduler_node_initialized = true;
 
-  _Scheduler_Update_priority( the_thread, priority );
-
   /* POSIX Keys */
   _RBTree_Initialize_empty( &the_thread->Keys.Key_value_pairs );
   _ISR_lock_Initialize( &the_thread->Keys.Lock, "POSIX Key Value Pairs" );