score: Simplify _Thread_Change_priority()

The function to change a thread priority was too complex.  Simplify it
with a new scheduler operation.  This increases the average case
performance due to the simplified logic.  The interrupt disabled
critical section is a bit prolonged since now the extract, update and
enqueue steps are executed atomically.  This should however not impact
the worst-case interrupt latency since at least for the Deterministic
Priority Scheduler this sequence can be carried out with a wee bit of
instructions and no loops.

Add _Scheduler_Change_priority() to replace the sequence of
  - _Thread_Set_transient(),
  - _Scheduler_Extract(),
  - _Scheduler_Enqueue(), and
  - _Scheduler_Enqueue_first().

Delete STATES_TRANSIENT, _States_Is_transient() and
_Thread_Set_transient() since this state is now superfluous.

With this change it is possible to get rid of the
SCHEDULER_SMP_NODE_IN_THE_AIR state.  This considerably simplifies the
implementation of the new SMP locking protocols.

22 files changed, 264 insertions, 550 deletions

diff --git a/cpukit/score/src/schedulercbsunblock.c b/cpukit/score/src/schedulercbsunblock.c
index 411e6cef27..1a374f64a6 100644
--- a/cpukit/score/src/schedulercbsunblock.c
+++ b/cpukit/score/src/schedulercbsunblock.c
@@ -20,6 +20,7 @@
 #endif
 
 #include <rtems/score/schedulercbsimpl.h>
+#include <rtems/score/scheduleredfimpl.h>
 #include <rtems/score/schedulerimpl.h>
 #include <rtems/score/threadimpl.h>
 #include <rtems/score/watchdogimpl.h>
diff --git a/cpukit/score/src/scheduleredfextract.c b/cpukit/score/src/scheduleredfchangepriority.c
index 94fde0a05c..dfcfef52d1 100644
--- a/cpukit/score/src/scheduleredfextract.c
+++ b/cpukit/score/src/scheduleredfchangepriority.c
@@ -20,9 +20,11 @@
 
 #include <rtems/score/scheduleredfimpl.h>
 
-void _Scheduler_EDF_Extract(
+void _Scheduler_EDF_Change_priority(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
+  Thread_Control          *the_thread,
+  Priority_Control         new_priority,
+  bool                     prepend_it
 )
 {
   Scheduler_EDF_Context *context =
@@ -30,5 +32,5 @@ void _Scheduler_EDF_Extract(
   Scheduler_EDF_Node *node = _Scheduler_EDF_Node_get( the_thread );
 
   _RBTree_Extract( &context->Ready, &node->Node );
-  node->queue_state = SCHEDULER_EDF_QUEUE_STATE_NOT_PRESENTLY;
+  _RBTree_Insert( &context->Ready, &node->Node );
 }
diff --git a/cpukit/score/src/scheduleredfenqueue.c b/cpukit/score/src/scheduleredfenqueue.c
deleted file mode 100644
index 8973d8b32c..0000000000
--- a/cpukit/score/src/scheduleredfenqueue.c
+++ /dev/null
@@ -1,34 +0,0 @@
-/**
- * @file
- *
- * @brief Scheduler EDF Enqueue
- * @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_Enqueue(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  Scheduler_EDF_Context *context =
-    _Scheduler_EDF_Get_context( scheduler );
-  Scheduler_EDF_Node *node = _Scheduler_EDF_Node_get( the_thread );
-
-  _RBTree_Insert( &context->Ready, &node->Node );
-  node->queue_state = SCHEDULER_EDF_QUEUE_STATE_YES;
-}
diff --git a/cpukit/score/src/scheduleredfenqueuefirst.c b/cpukit/score/src/scheduleredfenqueuefirst.c
deleted file mode 100644
index aafc9b4a21..0000000000
--- a/cpukit/score/src/scheduleredfenqueuefirst.c
+++ /dev/null
@@ -1,32 +0,0 @@
-/**
- * @file
- *
- * @brief Enqueues a thread to the ready queue
- *
- * @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/system.h>
-#include <rtems/config.h>
-#include <rtems/score/scheduleredf.h>
-
-void _Scheduler_EDF_Enqueue_first(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  _Scheduler_EDF_Enqueue( scheduler, the_thread );
-}
diff --git a/cpukit/score/src/scheduleredfunblock.c b/cpukit/score/src/scheduleredfunblock.c
index 7418b64e6a..30fa4f0163 100644
--- a/cpukit/score/src/scheduleredfunblock.c
+++ b/cpukit/score/src/scheduleredfunblock.c
@@ -18,7 +18,7 @@
 #include "config.h"
 #endif
 
-#include <rtems/score/scheduleredf.h>
+#include <rtems/score/scheduleredfimpl.h>
 #include <rtems/score/schedulerimpl.h>
 #include <rtems/score/thread.h>
 
diff --git a/cpukit/score/src/schedulerprioritychangepriority.c b/cpukit/score/src/schedulerprioritychangepriority.c
new file mode 100644
index 0000000000..448c603861
--- /dev/null
+++ b/cpukit/score/src/schedulerprioritychangepriority.c
@@ -0,0 +1,61 @@
+/**
+ * @file
+ *
+ * @brief Removes Thread from Thread Queue
+ *
+ * @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/schedulerpriorityimpl.h>
+
+void _Scheduler_priority_Change_priority(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Priority_Control         new_priority,
+  bool                     prepend_it
+)
+{
+  Scheduler_priority_Context *context =
+    _Scheduler_priority_Get_context( scheduler );
+  Scheduler_priority_Node *node = _Scheduler_priority_Node_get( the_thread );
+
+  _Scheduler_priority_Ready_queue_extract(
+    the_thread,
+    &node->Ready_queue,
+    &context->Bit_map
+  );
+
+  _Scheduler_priority_Ready_queue_update(
+    &node->Ready_queue,
+    new_priority,
+    &context->Bit_map,
+    &context->Ready[ 0 ]
+  );
+
+  if ( prepend_it ) {
+    _Scheduler_priority_Ready_queue_enqueue_first(
+      the_thread,
+      &node->Ready_queue,
+      &context->Bit_map
+    );
+  } else {
+    _Scheduler_priority_Ready_queue_enqueue(
+      the_thread,
+      &node->Ready_queue,
+      &context->Bit_map
+    );
+  }
+}
diff --git a/cpukit/score/src/schedulerpriorityenqueue.c b/cpukit/score/src/schedulerpriorityenqueue.c
deleted file mode 100644
index aa901cc978..0000000000
--- a/cpukit/score/src/schedulerpriorityenqueue.c
+++ /dev/null
@@ -1,37 +0,0 @@
-/**
- *  @file
- *
- *  @brief Scheduler Priority Enqueue
- *  @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/schedulerpriorityimpl.h>
-
-void _Scheduler_priority_Enqueue(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  Scheduler_priority_Context *context =
-    _Scheduler_priority_Get_context( scheduler );
-  Scheduler_priority_Node *node = _Scheduler_priority_Node_get( the_thread );
-
-  _Scheduler_priority_Ready_queue_enqueue(
-    the_thread,
-    &node->Ready_queue,
-    &context->Bit_map
-  );
-}
diff --git a/cpukit/score/src/schedulerpriorityenqueuefirst.c b/cpukit/score/src/schedulerpriorityenqueuefirst.c
deleted file mode 100644
index 1714fe57f0..0000000000
--- a/cpukit/score/src/schedulerpriorityenqueuefirst.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/**
- *  @file
- *
- *  @brief Scheduler Priority Enqueue First
- *  @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/schedulerpriorityimpl.h>
-
-void _Scheduler_priority_Enqueue_first(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  Scheduler_priority_Context *context =
-    _Scheduler_priority_Get_context( scheduler );
-  Scheduler_priority_Node *node = _Scheduler_priority_Node_get( the_thread );
-
-  _Scheduler_priority_Ready_queue_enqueue_first(
-    the_thread,
-    &node->Ready_queue,
-    &context->Bit_map
-  );
-}
-
diff --git a/cpukit/score/src/schedulerpriorityextract.c b/cpukit/score/src/schedulerpriorityextract.c
deleted file mode 100644
index 84dbaa4280..0000000000
--- a/cpukit/score/src/schedulerpriorityextract.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/**
- * @file
- *
- * @brief Removes Thread from Thread Queue
- *
- * @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/schedulerpriorityimpl.h>
-
-void _Scheduler_priority_Extract(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  _Scheduler_priority_Extract_body( scheduler, the_thread );
-}
diff --git a/cpukit/score/src/schedulerprioritysmp.c b/cpukit/score/src/schedulerprioritysmp.c
index 8133956fbd..dbf7b0c38b 100644
--- a/cpukit/score/src/schedulerprioritysmp.c
+++ b/cpukit/score/src/schedulerprioritysmp.c
@@ -27,7 +27,6 @@
 #include <rtems/score/schedulerprioritysmp.h>
 #include <rtems/score/schedulerpriorityimpl.h>
 #include <rtems/score/schedulersmpimpl.h>
-#include <rtems/score/wkspace.h>
 
 static Scheduler_priority_SMP_Context *
 _Scheduler_priority_SMP_Get_context( const Scheduler_Control *scheduler )
@@ -48,6 +47,13 @@ static Scheduler_priority_SMP_Node *_Scheduler_priority_SMP_Node_get(
   return (Scheduler_priority_SMP_Node *) _Scheduler_Node_get( thread );
 }
 
+static Scheduler_priority_SMP_Node *_Scheduler_priority_SMP_Node_downcast(
+  Scheduler_Node *node
+)
+{
+  return (Scheduler_priority_SMP_Node *) node;
+}
+
 void _Scheduler_priority_SMP_Initialize( const Scheduler_Control *scheduler )
 {
   Scheduler_priority_SMP_Context *self =
@@ -70,40 +76,47 @@ bool _Scheduler_priority_SMP_Allocate(
   return true;
 }
 
-void _Scheduler_priority_SMP_Update(
-  const Scheduler_Control *scheduler,
-  Thread_Control *thread
+static void _Scheduler_priority_SMP_Do_update(
+  Scheduler_Context *context,
+  Scheduler_Node *base_node,
+  Priority_Control new_priority
 )
 {
   Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_context( scheduler );
+    _Scheduler_priority_SMP_Get_self( context );
   Scheduler_priority_SMP_Node *node =
-    _Scheduler_priority_SMP_Node_get( thread );
+    _Scheduler_priority_SMP_Node_downcast( base_node );
 
   _Scheduler_priority_Ready_queue_update(
-    thread,
     &node->Ready_queue,
+    new_priority,
     &self->Bit_map,
     &self->Ready[ 0 ]
   );
 }
 
+void _Scheduler_priority_SMP_Update(
+  const Scheduler_Control *scheduler,
+  Thread_Control *thread
+)
+{
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
+  Scheduler_Node *node = _Scheduler_Node_get( thread );
+
+  _Scheduler_priority_SMP_Do_update( context, node, thread->current_priority );
+}
+
 static Thread_Control *_Scheduler_priority_SMP_Get_highest_ready(
   Scheduler_Context *context
 )
 {
   Scheduler_priority_SMP_Context *self =
     _Scheduler_priority_SMP_Get_self( context );
-  Thread_Control *highest_ready = NULL;
-
-  if ( !_Priority_bit_map_Is_empty( &self->Bit_map ) ) {
-    highest_ready = _Scheduler_priority_Ready_queue_first(
-      &self->Bit_map,
-      &self->Ready[ 0 ]
-    );
-  }
 
-  return highest_ready;
+  return _Scheduler_priority_Ready_queue_first(
+    &self->Bit_map,
+    &self->Ready[ 0 ]
+  );
 }
 
 static void _Scheduler_priority_SMP_Move_from_scheduled_to_ready(
@@ -179,7 +192,7 @@ static void _Scheduler_priority_SMP_Insert_ready_fifo(
   );
 }
 
-static void _Scheduler_priority_SMP_Do_extract(
+static void _Scheduler_priority_SMP_Extract_from_ready(
   Scheduler_Context *context,
   Thread_Control *thread
 )
@@ -189,23 +202,11 @@ static void _Scheduler_priority_SMP_Do_extract(
   Scheduler_priority_SMP_Node *node =
     _Scheduler_priority_SMP_Node_get( thread );
 
-  if ( node->Base.state == SCHEDULER_SMP_NODE_SCHEDULED ) {
-    _Scheduler_SMP_Node_change_state(
-      &node->Base,
-      SCHEDULER_SMP_NODE_IN_THE_AIR
-    );
-    _Chain_Extract_unprotected( &thread->Object.Node );
-  } else {
-    _Scheduler_SMP_Node_change_state(
-      &node->Base,
-      SCHEDULER_SMP_NODE_BLOCKED
-    );
-    _Scheduler_priority_Ready_queue_extract(
-      thread,
-      &node->Ready_queue,
-      &self->Bit_map
-    );
-  }
+  _Scheduler_priority_Ready_queue_extract(
+    thread,
+    &node->Ready_queue,
+    &self->Bit_map
+  );
 }
 
 void _Scheduler_priority_SMP_Block(
@@ -213,13 +214,12 @@ void _Scheduler_priority_SMP_Block(
   Thread_Control *thread
 )
 {
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_context( scheduler );
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
 
   _Scheduler_SMP_Block(
-    &self->Base.Base,
+    context,
     thread,
-    _Scheduler_priority_SMP_Do_extract,
+    _Scheduler_priority_SMP_Extract_from_ready,
     _Scheduler_priority_SMP_Get_highest_ready,
     _Scheduler_priority_SMP_Move_from_ready_to_scheduled
   );
@@ -228,6 +228,7 @@ void _Scheduler_priority_SMP_Block(
 static void _Scheduler_priority_SMP_Enqueue_ordered(
   Scheduler_Context *context,
   Thread_Control *thread,
+  bool has_processor_allocated,
   Chain_Node_order order,
   Scheduler_SMP_Insert insert_ready,
   Scheduler_SMP_Insert insert_scheduled
@@ -236,6 +237,7 @@ static void _Scheduler_priority_SMP_Enqueue_ordered(
   _Scheduler_SMP_Enqueue_ordered(
     context,
     thread,
+    has_processor_allocated,
     order,
     _Scheduler_priority_SMP_Get_highest_ready,
     insert_ready,
@@ -245,52 +247,66 @@ static void _Scheduler_priority_SMP_Enqueue_ordered(
   );
 }
 
-void _Scheduler_priority_SMP_Enqueue_lifo(
-  const Scheduler_Control *scheduler,
-  Thread_Control *thread
+static void _Scheduler_priority_SMP_Enqueue_lifo(
+  Scheduler_Context *context,
+  Thread_Control *thread,
+  bool has_processor_allocated
 )
 {
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_context( scheduler );
-
   _Scheduler_priority_SMP_Enqueue_ordered(
-    &self->Base.Base,
+    context,
     thread,
+    has_processor_allocated,
     _Scheduler_simple_Insert_priority_lifo_order,
     _Scheduler_priority_SMP_Insert_ready_lifo,
     _Scheduler_SMP_Insert_scheduled_lifo
   );
 }
 
-void _Scheduler_priority_SMP_Enqueue_fifo(
-  const Scheduler_Control *scheduler,
-  Thread_Control *thread
+static void _Scheduler_priority_SMP_Enqueue_fifo(
+  Scheduler_Context *context,
+  Thread_Control *thread,
+  bool has_processor_allocated
 )
 {
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_context( scheduler );
-
   _Scheduler_priority_SMP_Enqueue_ordered(
-    &self->Base.Base,
+    context,
     thread,
+    has_processor_allocated,
     _Scheduler_simple_Insert_priority_fifo_order,
     _Scheduler_priority_SMP_Insert_ready_fifo,
     _Scheduler_SMP_Insert_scheduled_fifo
   );
 }
 
-void _Scheduler_priority_SMP_Extract(
+void _Scheduler_priority_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control *thread
 )
 {
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_context( scheduler );
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
 
-  _Scheduler_SMP_Extract(
-    &self->Base.Base,
+  _Scheduler_priority_SMP_Enqueue_fifo( context, thread, false );
+}
+
+void _Scheduler_priority_SMP_Change_priority(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *thread,
+  Priority_Control         new_priority,
+  bool                     prepend_it
+)
+{
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
+
+  _Scheduler_SMP_Change_priority(
+    context,
     thread,
-    _Scheduler_priority_SMP_Do_extract
+    new_priority,
+    prepend_it,
+    _Scheduler_priority_SMP_Extract_from_ready,
+    _Scheduler_priority_SMP_Do_update,
+    _Scheduler_priority_SMP_Enqueue_fifo,
+    _Scheduler_priority_SMP_Enqueue_lifo
   );
 }
 
@@ -299,12 +315,13 @@ void _Scheduler_priority_SMP_Yield(
   Thread_Control *thread
 )
 {
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
   ISR_Level level;
 
   _ISR_Disable( level );
 
-  _Scheduler_priority_SMP_Extract( scheduler, thread );
-  _Scheduler_priority_SMP_Enqueue_fifo( scheduler, thread );
+  _Scheduler_SMP_Extract_from_scheduled( thread );
+  _Scheduler_priority_SMP_Enqueue_fifo( context, thread, true );
 
   _ISR_Enable( level );
 }
@@ -314,15 +331,8 @@ void _Scheduler_priority_SMP_Schedule(
   Thread_Control *thread
 )
 {
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_context( scheduler );
-
-  _Scheduler_SMP_Schedule(
-    &self->Base.Base,
-    thread,
-    _Scheduler_priority_SMP_Get_highest_ready,
-    _Scheduler_priority_SMP_Move_from_ready_to_scheduled
-  );
+  (void) scheduler;
+  (void) thread;
 }
 
 void _Scheduler_priority_SMP_Start_idle(
@@ -331,8 +341,7 @@ void _Scheduler_priority_SMP_Start_idle(
   Per_CPU_Control *cpu
 )
 {
-  Scheduler_priority_SMP_Context *self =
-    _Scheduler_priority_SMP_Get_context( scheduler );
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
 
-  _Scheduler_SMP_Start_idle( &self->Base.Base, thread, cpu );
+  _Scheduler_SMP_Start_idle( context, thread, cpu );
 }
diff --git a/cpukit/score/src/schedulerpriorityupdate.c b/cpukit/score/src/schedulerpriorityupdate.c
index 8a22ee662d..e58a6091a3 100644
--- a/cpukit/score/src/schedulerpriorityupdate.c
+++ b/cpukit/score/src/schedulerpriorityupdate.c
@@ -30,8 +30,8 @@ void _Scheduler_priority_Update(
   Scheduler_priority_Node *node = _Scheduler_priority_Node_get( the_thread );
 
   _Scheduler_priority_Ready_queue_update(
-    the_thread,
     &node->Ready_queue,
+    the_thread->current_priority,
     &context->Bit_map,
     &context->Ready[ 0 ]
   );
diff --git a/cpukit/score/src/schedulersimplereadyqueueenqueue.c b/cpukit/score/src/schedulersimplechangepriority.c
index 8e5f12d6ee..010f1dfc79 100644
--- a/cpukit/score/src/schedulersimplereadyqueueenqueue.c
+++ b/cpukit/score/src/schedulersimplechangepriority.c
@@ -1,7 +1,8 @@
 /**
  * @file
  *
- * @brief Scheduler Simple Priority Enqueue Ready Thread
+ * @brief Removes a Thread from the Simple Queue
+ *
  * @ingroup ScoreScheduler
  */
 
@@ -20,13 +21,21 @@
 
 #include <rtems/score/schedulersimpleimpl.h>
 
-void _Scheduler_simple_Ready_queue_enqueue(
+void _Scheduler_simple_Change_priority(
   const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
+  Thread_Control          *the_thread,
+  Priority_Control         new_priority,
+  bool                     prepend_it
 )
 {
   Scheduler_simple_Context *context =
     _Scheduler_simple_Get_context( scheduler );
 
-  _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
+  _Scheduler_simple_Extract( scheduler, the_thread );
+
+  if ( prepend_it ) {
+    _Scheduler_simple_Insert_priority_lifo( &context->Ready, the_thread );
+  } else {
+    _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
+  }
 }
diff --git a/cpukit/score/src/schedulersimpleenqueue.c b/cpukit/score/src/schedulersimpleenqueue.c
deleted file mode 100644
index 5dc88948da..0000000000
--- a/cpukit/score/src/schedulersimpleenqueue.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/**
- * @file
- *
- * @brief Puts Thread onto the Ready Queue
- *
- * @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/schedulersimpleimpl.h>
-
-void _Scheduler_simple_Enqueue(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  _Scheduler_simple_Ready_queue_enqueue( scheduler, the_thread );
-}
diff --git a/cpukit/score/src/schedulersimpleenqueuefirst.c b/cpukit/score/src/schedulersimpleenqueuefirst.c
deleted file mode 100644
index 2ea0a15917..0000000000
--- a/cpukit/score/src/schedulersimpleenqueuefirst.c
+++ /dev/null
@@ -1,29 +0,0 @@
-/**
- *  @file
- *
- *  @brief Scheduler Simple Enqueue First
- *  @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/schedulersimple.h>
-
-void _Scheduler_simple_Enqueue_first(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  _Scheduler_simple_Ready_queue_enqueue_first( scheduler, the_thread );
-}
diff --git a/cpukit/score/src/schedulersimpleextract.c b/cpukit/score/src/schedulersimpleextract.c
deleted file mode 100644
index 6b89c99881..0000000000
--- a/cpukit/score/src/schedulersimpleextract.c
+++ /dev/null
@@ -1,32 +0,0 @@
-/**
- * @file
- *
- * @brief Removes a Thread from the Simple Queue
- *
- * @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/schedulersimpleimpl.h>
-
-void _Scheduler_simple_Extract(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  (void) scheduler;
-
-  _Chain_Extract_unprotected( &the_thread->Object.Node );
-}
diff --git a/cpukit/score/src/schedulersimplereadyqueueenqueuefirst.c b/cpukit/score/src/schedulersimplereadyqueueenqueuefirst.c
deleted file mode 100644
index c5f1e68597..0000000000
--- a/cpukit/score/src/schedulersimplereadyqueueenqueuefirst.c
+++ /dev/null
@@ -1,32 +0,0 @@
-/**
- *  @file
- *
- *  @brief Scheduler Simple Ready Queue Enqueue First
- *  @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/schedulersimpleimpl.h>
-
-void _Scheduler_simple_Ready_queue_enqueue_first(
-  const Scheduler_Control *scheduler,
-  Thread_Control          *the_thread
-)
-{
-  Scheduler_simple_Context *context =
-    _Scheduler_simple_Get_context( scheduler );
-
-  _Scheduler_simple_Insert_priority_lifo( &context->Ready, the_thread );
-}
diff --git a/cpukit/score/src/schedulersimplesmp.c b/cpukit/score/src/schedulersimplesmp.c
index 8436659df4..a971ee1b64 100644
--- a/cpukit/score/src/schedulersimplesmp.c
+++ b/cpukit/score/src/schedulersimplesmp.c
@@ -20,7 +20,6 @@
 
 #include <rtems/score/schedulersimplesmp.h>
 #include <rtems/score/schedulersmpimpl.h>
-#include <rtems/score/wkspace.h>
 
 static Scheduler_simple_SMP_Context *
 _Scheduler_simple_SMP_Get_context( const Scheduler_Control *scheduler )
@@ -55,20 +54,25 @@ bool _Scheduler_simple_SMP_Allocate(
   return true;
 }
 
+static void _Scheduler_simple_SMP_Do_update(
+  Scheduler_Context *context,
+  Scheduler_Node *node,
+  Priority_Control new_priority
+)
+{
+  (void) context;
+  (void) node;
+  (void) new_priority;
+}
+
 static Thread_Control *_Scheduler_simple_SMP_Get_highest_ready(
   Scheduler_Context *context
 )
 {
   Scheduler_simple_SMP_Context *self =
     _Scheduler_simple_SMP_Get_self( context );
-  Thread_Control *highest_ready = NULL;
-  Chain_Control *ready = &self->Ready;
 
-  if ( !_Chain_Is_empty( ready ) ) {
-    highest_ready = (Thread_Control *) _Chain_First( ready );
-  }
-
-  return highest_ready;
+  return (Thread_Control *) _Chain_First( &self->Ready );
 }
 
 static void _Scheduler_simple_SMP_Move_from_scheduled_to_ready(
@@ -131,21 +135,13 @@ static void _Scheduler_simple_SMP_Insert_ready_fifo(
   );
 }
 
-static void _Scheduler_simple_SMP_Do_extract(
+static void _Scheduler_simple_SMP_Extract_from_ready(
   Scheduler_Context *context,
   Thread_Control *thread
 )
 {
-  Scheduler_SMP_Node *node = _Scheduler_SMP_Node_get( thread );
-
   (void) context;
 
-  if ( node->state == SCHEDULER_SMP_NODE_SCHEDULED ) {
-    _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_IN_THE_AIR );
-  } else {
-    _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_BLOCKED );
-  }
-
   _Chain_Extract_unprotected( &thread->Object.Node );
 }
 
@@ -154,13 +150,12 @@ void _Scheduler_simple_SMP_Block(
   Thread_Control *thread
 )
 {
-  Scheduler_simple_SMP_Context *self =
-    _Scheduler_simple_SMP_Get_context( scheduler );
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
 
   _Scheduler_SMP_Block(
-    &self->Base.Base,
+    context,
     thread,
-    _Scheduler_simple_SMP_Do_extract,
+    _Scheduler_simple_SMP_Extract_from_ready,
     _Scheduler_simple_SMP_Get_highest_ready,
     _Scheduler_simple_SMP_Move_from_ready_to_scheduled
   );
@@ -169,6 +164,7 @@ void _Scheduler_simple_SMP_Block(
 static void _Scheduler_simple_SMP_Enqueue_ordered(
   Scheduler_Context *context,
   Thread_Control *thread,
+  bool has_processor_allocated,
   Chain_Node_order order,
   Scheduler_SMP_Insert insert_ready,
   Scheduler_SMP_Insert insert_scheduled
@@ -177,6 +173,7 @@ static void _Scheduler_simple_SMP_Enqueue_ordered(
   _Scheduler_SMP_Enqueue_ordered(
     context,
     thread,
+    has_processor_allocated,
     order,
     _Scheduler_simple_SMP_Get_highest_ready,
     insert_ready,
@@ -186,52 +183,66 @@ static void _Scheduler_simple_SMP_Enqueue_ordered(
   );
 }
 
-void _Scheduler_simple_SMP_Enqueue_priority_lifo(
-  const Scheduler_Control *scheduler,
-  Thread_Control *thread
+static void _Scheduler_simple_SMP_Enqueue_lifo(
+  Scheduler_Context *context,
+  Thread_Control *thread,
+  bool has_processor_allocated
 )
 {
-  Scheduler_simple_SMP_Context *self =
-    _Scheduler_simple_SMP_Get_context( scheduler );
-
   _Scheduler_simple_SMP_Enqueue_ordered(
-    &self->Base.Base,
+    context,
     thread,
+    has_processor_allocated,
     _Scheduler_simple_Insert_priority_lifo_order,
     _Scheduler_simple_SMP_Insert_ready_lifo,
     _Scheduler_SMP_Insert_scheduled_lifo
   );
 }
 
-void _Scheduler_simple_SMP_Enqueue_priority_fifo(
-  const Scheduler_Control *scheduler,
-  Thread_Control *thread
+static void _Scheduler_simple_SMP_Enqueue_fifo(
+  Scheduler_Context *context,
+  Thread_Control *thread,
+  bool has_processor_allocated
 )
 {
-  Scheduler_simple_SMP_Context *self =
-    _Scheduler_simple_SMP_Get_context( scheduler );
-
   _Scheduler_simple_SMP_Enqueue_ordered(
-    &self->Base.Base,
+    context,
     thread,
+    has_processor_allocated,
     _Scheduler_simple_Insert_priority_fifo_order,
     _Scheduler_simple_SMP_Insert_ready_fifo,
     _Scheduler_SMP_Insert_scheduled_fifo
   );
 }
 
-void _Scheduler_simple_SMP_Extract(
+void _Scheduler_simple_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control *thread
 )
 {
-  Scheduler_simple_SMP_Context *self =
-    _Scheduler_simple_SMP_Get_context( scheduler );
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
+
+  _Scheduler_simple_SMP_Enqueue_fifo( context, thread, false );
+}
 
-  _Scheduler_SMP_Extract(
-    &self->Base.Base,
+void _Scheduler_simple_SMP_Change_priority(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *thread,
+  Priority_Control         new_priority,
+  bool                     prepend_it
+)
+{
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
+
+  _Scheduler_SMP_Change_priority(
+    context,
     thread,
-    _Scheduler_simple_SMP_Do_extract
+    new_priority,
+    prepend_it,
+    _Scheduler_simple_SMP_Extract_from_ready,
+    _Scheduler_simple_SMP_Do_update,
+    _Scheduler_simple_SMP_Enqueue_fifo,
+    _Scheduler_simple_SMP_Enqueue_lifo
   );
 }
 
@@ -240,12 +251,13 @@ void _Scheduler_simple_SMP_Yield(
   Thread_Control *thread
 )
 {
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
   ISR_Level level;
 
   _ISR_Disable( level );
 
-  _Scheduler_simple_SMP_Extract( scheduler, thread );
-  _Scheduler_simple_SMP_Enqueue_priority_fifo( scheduler, thread );
+  _Scheduler_SMP_Extract_from_scheduled( thread );
+  _Scheduler_simple_SMP_Enqueue_fifo( context, thread, true );
 
   _ISR_Enable( level );
 }
@@ -255,15 +267,8 @@ void _Scheduler_simple_SMP_Schedule(
   Thread_Control *thread
 )
 {
-  Scheduler_simple_SMP_Context *self =
-    _Scheduler_simple_SMP_Get_context( scheduler );
-
-  _Scheduler_SMP_Schedule(
-    &self->Base.Base,
-    thread,
-    _Scheduler_simple_SMP_Get_highest_ready,
-    _Scheduler_simple_SMP_Move_from_ready_to_scheduled
-  );
+  (void) scheduler;
+  (void) thread;
 }
 
 void _Scheduler_simple_SMP_Start_idle(
@@ -272,8 +277,7 @@ void _Scheduler_simple_SMP_Start_idle(
   Per_CPU_Control *cpu
 )
 {
-  Scheduler_simple_SMP_Context *self =
-    _Scheduler_simple_SMP_Get_context( scheduler );
+  Scheduler_Context *context = _Scheduler_Get_context( scheduler );
 
-  _Scheduler_SMP_Start_idle( &self->Base.Base, thread, cpu );
+  _Scheduler_SMP_Start_idle( context, thread, cpu );
 }
diff --git a/cpukit/score/src/schedulersimpleunblock.c b/cpukit/score/src/schedulersimpleunblock.c
index 3a9528fba5..4e49bd6697 100644
--- a/cpukit/score/src/schedulersimpleunblock.c
+++ b/cpukit/score/src/schedulersimpleunblock.c
@@ -26,7 +26,10 @@ void _Scheduler_simple_Unblock(
   Thread_Control          *the_thread
 )
 {
-  _Scheduler_simple_Ready_queue_enqueue( scheduler, the_thread );
+  Scheduler_simple_Context *context =
+    _Scheduler_simple_Get_context( scheduler );
+
+  _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
 
   /*
    *  If the thread that was unblocked is more important than the heir,
diff --git a/cpukit/score/src/schedulersimpleyield.c b/cpukit/score/src/schedulersimpleyield.c
index ea41892ad0..65578d0bbb 100644
--- a/cpukit/score/src/schedulersimpleyield.c
+++ b/cpukit/score/src/schedulersimpleyield.c
@@ -26,11 +26,14 @@ void _Scheduler_simple_Yield(
   Thread_Control          *the_thread
 )
 {
+  Scheduler_simple_Context *context =
+    _Scheduler_simple_Get_context( scheduler );
   ISR_Level       level;
 
   _ISR_Disable( level );
 
-    _Scheduler_simple_Ready_queue_requeue( scheduler, the_thread );
+    _Chain_Extract_unprotected( &the_thread->Object.Node );
+    _Scheduler_simple_Insert_priority_fifo( &context->Ready, the_thread );
 
     _ISR_Flash( level );
 
diff --git a/cpukit/score/src/schedulersmpvalidstatechanges.c b/cpukit/score/src/schedulersmpvalidstatechanges.c
index 61f6a7e2d5..6a5dcc6de4 100644
--- a/cpukit/score/src/schedulersmpvalidstatechanges.c
+++ b/cpukit/score/src/schedulersmpvalidstatechanges.c
@@ -30,10 +30,9 @@
  * Table with all valid state transitions.  It is used in
  * _Scheduler_SMP_Node_change_state() in case RTEMS_DEBUG is defined.
  */
-const bool _Scheduler_SMP_Node_valid_state_changes[ 4 ][ 4 ] = {
-  /*                 BLOCKED SCHEDULED READY  IN THE AIR */
-  /* BLOCKED    */ { false,  true,     true,  false },
-  /* SCHEDULED  */ { false,  false,    true,  true },
-  /* READY      */ { true,   true,     false, false },
-  /* IN THE AIR */ { true,   true,     true,  false }
+const bool _Scheduler_SMP_Node_valid_state_changes[ 3 ][ 3 ] = {
+  /* FROM / TO       BLOCKED SCHEDULED READY */
+  /* BLOCKED    */ { false,  true,     true },
+  /* SCHEDULED  */ { true,   false,    true },
+  /* READY      */ { true,   true,     false }
 };
diff --git a/cpukit/score/src/threadchangepriority.c b/cpukit/score/src/threadchangepriority.c
index 68eb3e89fa..4480b536d0 100644
--- a/cpukit/score/src/threadchangepriority.c
+++ b/cpukit/score/src/threadchangepriority.c
@@ -29,79 +29,40 @@ void _Thread_Change_priority(
   bool              prepend_it
 )
 {
-  const Scheduler_Control *scheduler = _Scheduler_Get( the_thread );
-  ISR_Level                level;
-  States_Control           state, original_state;
-
-  /*
-   * Save original state
-   */
-  original_state = the_thread->current_state;
-
-  /*
-   * Set a transient state for the thread so it is pulled off the Ready chains.
-   * This will prevent it from being scheduled no matter what happens in an
-   * ISR.
-   */
-  _Thread_Set_transient( the_thread );
-
   /*
    *  Do not bother recomputing all the priority related information if
    *  we are not REALLY changing priority.
    */
- if ( the_thread->current_priority != new_priority )
-    _Thread_Set_priority( the_thread, new_priority );
-
-  _ISR_Disable( level );
-
-  /*
-   *  If the thread has more than STATES_TRANSIENT set, then it is blocked,
-   *  If it is blocked on a thread queue, then we need to requeue it.
-   */
-  state = the_thread->current_state;
-  if ( state != STATES_TRANSIENT ) {
-    /* Only clear the transient state if it wasn't set already */
-    if ( ! _States_Is_transient( original_state ) )
-      the_thread->current_state = _States_Clear( STATES_TRANSIENT, state );
-
-    /*
-     * The thread may have new blocking states added by interrupt service
-     * routines after the change into the transient state.  This will not
-     * result in a _Scheduler_Block() operation.  Make sure we select an heir
-     * now.
-     */
-    _Scheduler_Schedule( scheduler, the_thread );
-
-    _ISR_Enable( level );
-    if ( _States_Is_waiting_on_thread_queue( state ) ) {
-      _Thread_queue_Requeue( the_thread->Wait.queue, the_thread );
+  if ( the_thread->current_priority != new_priority ) {
+    ISR_Level                level;
+    const Scheduler_Control *scheduler;
+
+    _ISR_Disable( level );
+
+    scheduler = _Scheduler_Get( the_thread );
+    the_thread->current_priority = new_priority;
+
+    if ( _States_Is_ready( the_thread->current_state ) ) {
+      _Scheduler_Change_priority(
+        scheduler,
+        the_thread,
+        new_priority,
+        prepend_it
+      );
+
+      _ISR_Flash( level );
+
+      /*
+       *  We altered the set of thread priorities.  So let's figure out
+       *  who is the heir and if we need to switch to them.
+       */
+      scheduler = _Scheduler_Get( the_thread );
+      _Scheduler_Schedule( scheduler, the_thread );
+    } else {
+      _Scheduler_Update( scheduler, the_thread );
     }
-    return;
-  }
-
-  /* Only clear the transient state if it wasn't set already */
-  if ( ! _States_Is_transient( original_state ) ) {
-    /*
-     *  Interrupts are STILL disabled.
-     *  We now know the thread will be in the READY state when we remove
-     *  the TRANSIENT state.  So we have to place it on the appropriate
-     *  Ready Queue with interrupts off.
-     */
-    the_thread->current_state = _States_Clear( STATES_TRANSIENT, state );
+    _ISR_Enable( level );
 
-    if ( prepend_it )
-      _Scheduler_Enqueue_first( scheduler, the_thread );
-    else
-      _Scheduler_Enqueue( scheduler, the_thread );
+    _Thread_queue_Requeue( the_thread->Wait.queue, the_thread );
   }
-
-  _ISR_Flash( level );
-
-  /*
-   *  We altered the set of thread priorities.  So let's figure out
-   *  who is the heir and if we need to switch to them.
-   */
-  _Scheduler_Schedule( scheduler, the_thread );
-
-  _ISR_Enable( level );
 }
diff --git a/cpukit/score/src/threadsettransient.c b/cpukit/score/src/threadsettransient.c
deleted file mode 100644
index ead3c452a3..0000000000
--- a/cpukit/score/src/threadsettransient.c
+++ /dev/null
@@ -1,44 +0,0 @@
-/**
- * @file
- *
- * @brief Sets the Transient State for a Thread
- *
- * @ingroup ScoreThread
- */
-
-/*
- *  COPYRIGHT (c) 1989-2011.
- *  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/threadimpl.h>
-#include <rtems/score/isrlevel.h>
-#include <rtems/score/schedulerimpl.h>
-
-void _Thread_Set_transient(
-  Thread_Control *the_thread
-)
-{
-  ISR_Level             level;
-  uint32_t              old_state;
-
-  _ISR_Disable( level );
-
-  old_state = the_thread->current_state;
-  the_thread->current_state = _States_Set( STATES_TRANSIENT, old_state );
-
-  if ( _States_Is_ready( old_state ) ) {
-    _Scheduler_Extract( _Scheduler_Get( the_thread ), the_thread );
-  }
-
-  _ISR_Enable( level );
-
-}