score: Add SMP scheduler make/clean sticky

This patch fixes the following broken behaviour:

  While a thread is scheduled on a helping scheduler, while it does not
  own a MrsP semaphore, if it obtains a MrsP semaphore, then no
  scheduler node using an idle thread and the ceiling priority of the
  semaphore is unblocked for the home scheduler.

This could lead to priority inversion issues and is not in line
with the MrsP protocol.

Introduce two new scheduler operations which are only enabled if
RTEMS_SMP is defined.  The operations are used to make the scheduler
node of the home scheduler sticky and to clean the sticky property.
This helps to keep the sticky handing out of the frequently used
priority update operation.

Close #4532.

10 files changed, 378 insertions, 77 deletions

diff --git a/cpukit/include/rtems/score/mrspimpl.h b/cpukit/include/rtems/score/mrspimpl.h
index 3e64ad94e6..daa309e7cb 100644
--- a/cpukit/include/rtems/score/mrspimpl.h
+++ b/cpukit/include/rtems/score/mrspimpl.h
@@ -268,7 +268,7 @@ RTEMS_INLINE_ROUTINE Status_Control _MRSP_Claim_ownership(
   _MRSP_Set_owner( mrsp, executing );
   cpu_self = _Thread_queue_Dispatch_disable( queue_context );
   _MRSP_Release( mrsp, queue_context );
-  _Thread_Priority_and_sticky_update( executing, 1 );
+  _Thread_Priority_update_and_make_sticky( executing );
   _Thread_Dispatch_enable( cpu_self );
   return STATUS_SUCCESSFUL;
 }
@@ -384,13 +384,6 @@ RTEMS_INLINE_ROUTINE Status_Control _MRSP_Wait_for_ownership(
     _MRSP_Replace_priority( mrsp, executing, &ceiling_priority );
   } else {
     Per_CPU_Control *cpu_self;
-    int              sticky_level_change;
-
-    if ( status != STATUS_DEADLOCK ) {
-      sticky_level_change = -1;
-    } else {
-      sticky_level_change = 0;
-    }
 
     _ISR_lock_ISR_disable( &queue_context->Lock_context.Lock_context );
     _MRSP_Remove_priority( executing, &ceiling_priority, queue_context );
@@ -398,7 +391,13 @@ RTEMS_INLINE_ROUTINE Status_Control _MRSP_Wait_for_ownership(
       &queue_context->Lock_context.Lock_context
     );
     _ISR_lock_ISR_enable( &queue_context->Lock_context.Lock_context );
-    _Thread_Priority_and_sticky_update( executing, sticky_level_change );
+
+    if ( status != STATUS_DEADLOCK ) {
+      _Thread_Priority_update_and_clean_sticky( executing );
+    } else {
+      _Thread_Priority_update_ignore_sticky( executing );
+    }
+
     _Thread_Dispatch_enable( cpu_self );
   }
 
@@ -493,7 +492,7 @@ RTEMS_INLINE_ROUTINE Status_Control _MRSP_Surrender(
       &queue_context->Lock_context.Lock_context
     );
     _MRSP_Release( mrsp, queue_context );
-    _Thread_Priority_and_sticky_update( executing, -1 );
+    _Thread_Priority_update_and_clean_sticky( executing );
     _Thread_Dispatch_enable( cpu_self );
     return STATUS_SUCCESSFUL;
   }
diff --git a/cpukit/include/rtems/score/scheduler.h b/cpukit/include/rtems/score/scheduler.h
index ad9d630023..95b4414bea 100644
--- a/cpukit/include/rtems/score/scheduler.h
+++ b/cpukit/include/rtems/score/scheduler.h
@@ -135,6 +135,61 @@ typedef struct {
   );
 
   /**
+   * @brief Makes the node sticky.
+   *
+   * This operation is used by _Thread_Priority_update_and_make_sticky().  It
+   * is only called for the scheduler node of the home scheduler.
+   *
+   * Uniprocessor schedulers schould provide
+   * _Scheduler_default_Sticky_do_nothing() for this operation.
+   *
+   * SMP schedulers should provide this operation using
+   * _Scheduler_SMP_Make_sticky().
+   *
+   * The make and clean sticky operations are an optimization to simplify the
+   * control flow in the update priority operation.  The update priority
+   * operation is used for all scheduler nodes and not just the scheduler node
+   * of home schedulers.  The update priority operation is a commonly used
+   * operations together with block and unblock.  The make and clean sticky
+   * operations are used only in specific scenarios.
+   *
+   * @param scheduler is the scheduler of the node.
+   *
+   * @param[in, out] the_thread is the thread owning the node.
+   *
+   * @param[in, out] node is the scheduler node to make sticky.
+   */
+  void ( *make_sticky )(
+    const Scheduler_Control *scheduler,
+    Thread_Control          *the_thread,
+    Scheduler_Node          *node
+  );
+
+  /**
+   * @brief Cleans the sticky property from the node.
+   *
+   * This operation is used by _Thread_Priority_update_and_clean_sticky().  It
+   * is only called for the scheduler node of the home scheduler.
+   *
+   * Uniprocessor schedulers schould provide
+   * _Scheduler_default_Sticky_do_nothing() for this operation.
+   *
+   * SMP schedulers should provide this operation using
+   * _Scheduler_SMP_Clean_sticky().
+   *
+   * @param scheduler is the scheduler of the node.
+   *
+   * @param[in, out] the_thread is the thread owning the node.
+   *
+   * @param[in, out] node is the scheduler node to clean the sticky property.
+   */
+  void ( *clean_sticky )(
+    const Scheduler_Control *scheduler,
+    Thread_Control          *the_thread,
+    Scheduler_Node          *node
+  );
+
+  /**
    * @brief Pin thread operation.
    *
    * @param[in] scheduler The scheduler instance of the specified processor.
@@ -400,6 +455,24 @@ Priority_Control _Scheduler_default_Unmap_priority(
   /**
    * @brief Does nothing.
    *
+   * This default implementation for the make and clean sticky operations
+   * should be used by uniprocessor schedulers if SMP support is enabled.
+   *
+   * @param scheduler is an unused parameter.
+   *
+   * @param the_thread is an unused parameter.
+   *
+   * @param node is an unused parameter.
+   */
+  void _Scheduler_default_Sticky_do_nothing(
+    const Scheduler_Control *scheduler,
+    Thread_Control          *the_thread,
+    Scheduler_Node          *node
+  );
+
+  /**
+   * @brief Does nothing.
+   *
    * This default implementation for the thread pin or unpin operations should
    * be used by uniprocessor schedulers if SMP support is enabled.
    *
@@ -459,6 +532,8 @@ Priority_Control _Scheduler_default_Unmap_priority(
     NULL, \
     NULL, \
     NULL, \
+    _Scheduler_default_Sticky_do_nothing, \
+    _Scheduler_default_Sticky_do_nothing, \
     _Scheduler_default_Pin_or_unpin_do_nothing, \
     _Scheduler_default_Pin_or_unpin_do_nothing, \
     NULL, \
diff --git a/cpukit/include/rtems/score/scheduleredfsmp.h b/cpukit/include/rtems/score/scheduleredfsmp.h
index ec975ed12f..75865e5a6e 100644
--- a/cpukit/include/rtems/score/scheduleredfsmp.h
+++ b/cpukit/include/rtems/score/scheduleredfsmp.h
@@ -129,6 +129,8 @@ typedef struct {
     _Scheduler_EDF_SMP_Ask_for_help, \
     _Scheduler_EDF_SMP_Reconsider_help_request, \
     _Scheduler_EDF_SMP_Withdraw_node, \
+    _Scheduler_EDF_SMP_Make_sticky, \
+    _Scheduler_EDF_SMP_Clean_sticky, \
     _Scheduler_EDF_SMP_Pin, \
     _Scheduler_EDF_SMP_Unpin, \
     _Scheduler_EDF_SMP_Add_processor, \
@@ -249,6 +251,36 @@ void _Scheduler_EDF_SMP_Withdraw_node(
 );
 
 /**
+ * @brief Makes the node sticky.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to make sticky.
+ */
+void _Scheduler_EDF_SMP_Make_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
+ * @brief Cleans the sticky property from the node.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to clean the sticky property.
+ */
+void _Scheduler_EDF_SMP_Clean_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
  * @brief Pin thread operation.
  *
  * @param scheduler The scheduler instance of the specified processor.
diff --git a/cpukit/include/rtems/score/schedulerimpl.h b/cpukit/include/rtems/score/schedulerimpl.h
index 7319cc4e4c..eb279876c7 100644
--- a/cpukit/include/rtems/score/schedulerimpl.h
+++ b/cpukit/include/rtems/score/schedulerimpl.h
@@ -405,65 +405,6 @@ RTEMS_INLINE_ROUTINE void _Scheduler_Update_priority( Thread_Control *the_thread
 #endif
 }
 
-#if defined(RTEMS_SMP)
-/**
- * @brief Changes the sticky level of the home scheduler node and propagates a
- * priority change of a thread to the scheduler.
- *
- * @param the_thread The thread changing its priority or sticky level.
- *
- * @see _Scheduler_Update_priority().
- */
-RTEMS_INLINE_ROUTINE void _Scheduler_Priority_and_sticky_update(
-  Thread_Control *the_thread,
-  int             sticky_level_change
-)
-{
-  Chain_Node              *node;
-  const Chain_Node        *tail;
-  Scheduler_Node          *scheduler_node;
-  const Scheduler_Control *scheduler;
-  ISR_lock_Context         lock_context;
-
-  _Thread_Scheduler_process_requests( the_thread );
-
-  node = _Chain_First( &the_thread->Scheduler.Scheduler_nodes );
-  scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node );
-  scheduler = _Scheduler_Node_get_scheduler( scheduler_node );
-
-  _Scheduler_Acquire_critical( scheduler, &lock_context );
-
-  scheduler_node->sticky_level += sticky_level_change;
-  _Assert( scheduler_node->sticky_level >= 0 );
-
-  ( *scheduler->Operations.update_priority )(
-    scheduler,
-    the_thread,
-    scheduler_node
-  );
-
-  _Scheduler_Release_critical( scheduler, &lock_context );
-
-  tail = _Chain_Immutable_tail( &the_thread->Scheduler.Scheduler_nodes );
-  node = _Chain_Next( node );
-
-  while ( node != tail ) {
-    scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node );
-    scheduler = _Scheduler_Node_get_scheduler( scheduler_node );
-
-    _Scheduler_Acquire_critical( scheduler, &lock_context );
-    ( *scheduler->Operations.update_priority )(
-      scheduler,
-      the_thread,
-      scheduler_node
-    );
-    _Scheduler_Release_critical( scheduler, &lock_context );
-
-    node = _Chain_Next( node );
-  }
-}
-#endif
-
 /**
  * @brief Maps a thread priority from the user domain to the scheduler domain.
  *
diff --git a/cpukit/include/rtems/score/schedulerpriorityaffinitysmp.h b/cpukit/include/rtems/score/schedulerpriorityaffinitysmp.h
index e997e81128..d77629b39d 100644
--- a/cpukit/include/rtems/score/schedulerpriorityaffinitysmp.h
+++ b/cpukit/include/rtems/score/schedulerpriorityaffinitysmp.h
@@ -65,6 +65,8 @@ extern "C" {
     _Scheduler_priority_affinity_SMP_Ask_for_help, \
     _Scheduler_priority_affinity_SMP_Reconsider_help_request, \
     _Scheduler_priority_affinity_SMP_Withdraw_node, \
+    _Scheduler_priority_affinity_SMP_Make_sticky, \
+    _Scheduler_priority_affinity_SMP_Clean_sticky, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_priority_affinity_SMP_Add_processor, \
@@ -181,6 +183,36 @@ void _Scheduler_priority_affinity_SMP_Withdraw_node(
 );
 
 /**
+ * @brief Makes the node sticky.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to make sticky.
+ */
+void _Scheduler_priority_affinity_SMP_Make_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
+ * @brief Cleans the sticky property from the node.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to clean the sticky property.
+ */
+void _Scheduler_priority_affinity_SMP_Clean_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
  * @brief Adds @a idle to @a scheduler.
  *
  * @param[in, out] scheduler The scheduler instance to add the processor to.
diff --git a/cpukit/include/rtems/score/schedulerprioritysmp.h b/cpukit/include/rtems/score/schedulerprioritysmp.h
index fe314fb05b..9ece9ae143 100644
--- a/cpukit/include/rtems/score/schedulerprioritysmp.h
+++ b/cpukit/include/rtems/score/schedulerprioritysmp.h
@@ -93,6 +93,8 @@ typedef struct {
     _Scheduler_priority_SMP_Ask_for_help, \
     _Scheduler_priority_SMP_Reconsider_help_request, \
     _Scheduler_priority_SMP_Withdraw_node, \
+    _Scheduler_priority_SMP_Make_sticky, \
+    _Scheduler_priority_SMP_Clean_sticky, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_priority_SMP_Add_processor, \
@@ -215,6 +217,36 @@ void _Scheduler_priority_SMP_Withdraw_node(
 );
 
 /**
+ * @brief Makes the node sticky.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to make sticky.
+ */
+void _Scheduler_priority_SMP_Make_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
+ * @brief Cleans the sticky property from the node.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to clean the sticky property.
+ */
+void _Scheduler_priority_SMP_Clean_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
  * @brief Adds @a idle to @a scheduler.
  *
  * @param[in, out] scheduler The scheduler instance to add the processor to.
diff --git a/cpukit/include/rtems/score/schedulersimplesmp.h b/cpukit/include/rtems/score/schedulersimplesmp.h
index c8394781c9..3b6f43869e 100644
--- a/cpukit/include/rtems/score/schedulersimplesmp.h
+++ b/cpukit/include/rtems/score/schedulersimplesmp.h
@@ -75,6 +75,8 @@ typedef struct {
     _Scheduler_simple_SMP_Ask_for_help, \
     _Scheduler_simple_SMP_Reconsider_help_request, \
     _Scheduler_simple_SMP_Withdraw_node, \
+    _Scheduler_simple_SMP_Make_sticky, \
+    _Scheduler_simple_SMP_Clean_sticky, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_simple_SMP_Add_processor, \
@@ -195,6 +197,36 @@ void _Scheduler_simple_SMP_Withdraw_node(
 );
 
 /**
+ * @brief Makes the node sticky.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to make sticky.
+ */
+void _Scheduler_simple_SMP_Make_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
+ * @brief Cleans the sticky property from the node.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to clean the sticky property.
+ */
+void _Scheduler_simple_SMP_Clean_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
  * @brief Adds @a idle to @a scheduler.
  *
  * @param[in, out] scheduler The scheduler instance to add the processor to.
diff --git a/cpukit/include/rtems/score/schedulersmpimpl.h b/cpukit/include/rtems/score/schedulersmpimpl.h
index 04019a1540..731b15d4bf 100644
--- a/cpukit/include/rtems/score/schedulersmpimpl.h
+++ b/cpukit/include/rtems/score/schedulersmpimpl.h
@@ -1688,6 +1688,90 @@ static inline void _Scheduler_SMP_Withdraw_node(
 }
 
 /**
+ * @brief Makes the node sticky.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to make sticky.
+ */
+static inline void _Scheduler_SMP_Make_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node,
+  Scheduler_SMP_Update     update,
+  Scheduler_SMP_Enqueue    enqueue
+)
+{
+  Scheduler_SMP_Node_state node_state;
+
+  node_state = _Scheduler_SMP_Node_state( node );
+
+  if ( node_state == SCHEDULER_SMP_NODE_BLOCKED ) {
+    Scheduler_Context *context;
+    Priority_Control   insert_priority;
+    Priority_Control   priority;
+
+    context = _Scheduler_Get_context( scheduler );
+    priority = _Scheduler_Node_get_priority( node );
+    priority = SCHEDULER_PRIORITY_PURIFY( priority );
+
+    if ( priority != _Scheduler_SMP_Node_priority( node ) ) {
+      ( *update )( context, node, priority );
+    }
+
+    _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_READY );
+    insert_priority = SCHEDULER_PRIORITY_APPEND( priority );
+    (void) ( *enqueue )( context, node, insert_priority );
+  }
+}
+
+/**
+ * @brief Cleans the sticky property from the node.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to clean the sticky property.
+ */
+static inline void _Scheduler_SMP_Clean_sticky(
+  const Scheduler_Control          *scheduler,
+  Thread_Control                   *the_thread,
+  Scheduler_Node                   *node,
+  Scheduler_SMP_Extract             extract_from_scheduled,
+  Scheduler_SMP_Extract             extract_from_ready,
+  Scheduler_SMP_Get_highest_ready   get_highest_ready,
+  Scheduler_SMP_Move                move_from_ready_to_scheduled,
+  Scheduler_SMP_Allocate_processor  allocate_processor
+)
+{
+  Scheduler_SMP_Node_state node_state;
+
+  node_state = _Scheduler_SMP_Node_state( node );
+
+  if ( node_state == SCHEDULER_SMP_NODE_SCHEDULED && node->idle != NULL ) {
+    Scheduler_Context *context;
+
+    context = _Scheduler_Get_context( scheduler );
+    _Scheduler_SMP_Node_change_state( node, SCHEDULER_SMP_NODE_BLOCKED );
+
+    ( *extract_from_scheduled )( context, node );
+
+    _Scheduler_SMP_Schedule_highest_ready(
+      context,
+      node,
+      _Thread_Get_CPU( node->idle ),
+      extract_from_ready,
+      get_highest_ready,
+      move_from_ready_to_scheduled,
+      allocate_processor
+    );
+  }
+}
+
+/**
  * @brief Starts the idle thread on the given processor.
  *
  * @param context The scheduler context instance.
diff --git a/cpukit/include/rtems/score/schedulerstrongapa.h b/cpukit/include/rtems/score/schedulerstrongapa.h
index bbded1b493..8db3ae8634 100644
--- a/cpukit/include/rtems/score/schedulerstrongapa.h
+++ b/cpukit/include/rtems/score/schedulerstrongapa.h
@@ -161,6 +161,8 @@ typedef struct {
     _Scheduler_strong_APA_Ask_for_help, \
     _Scheduler_strong_APA_Reconsider_help_request, \
     _Scheduler_strong_APA_Withdraw_node, \
+    _Scheduler_strong_APA_Make_sticky, \
+    _Scheduler_strong_APA_Clean_sticky, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_default_Pin_or_unpin_not_supported, \
     _Scheduler_strong_APA_Add_processor, \
@@ -279,6 +281,66 @@ void _Scheduler_strong_APA_Withdraw_node(
 );
 
 /**
+ * @brief Makes the node sticky.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to make sticky.
+ */
+void _Scheduler_strong_APA_Make_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
+ * @brief Cleans the sticky property from the node.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to clean the sticky property.
+ */
+void _Scheduler_strong_APA_Clean_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
+ * @brief Makes the node sticky.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to make sticky.
+ */
+void _Scheduler_strong_APA_Make_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
+ * @brief Cleans the sticky property from the node.
+ *
+ * @param scheduler is the scheduler of the node.
+ *
+ * @param[in, out] the_thread is the thread owning the node.
+ *
+ * @param[in, out] node is the scheduler node to clean the sticky property.
+ */
+void _Scheduler_strong_APA_sticky(
+  const Scheduler_Control *scheduler,
+  Thread_Control          *the_thread,
+  Scheduler_Node          *node
+);
+
+/**
  * @brief Adds the idle thread to a processor.
  *
  * @param scheduler The scheduler control instance.
diff --git a/cpukit/include/rtems/score/threadimpl.h b/cpukit/include/rtems/score/threadimpl.h
index 934b56468a..a55524cfd1 100644
--- a/cpukit/include/rtems/score/threadimpl.h
+++ b/cpukit/include/rtems/score/threadimpl.h
@@ -790,17 +790,29 @@ void _Thread_Priority_replace(
  */
 void _Thread_Priority_update( Thread_queue_Context *queue_context );
 
+#if defined(RTEMS_SMP)
 /**
- * @brief Updates the priority of the thread and changes it sticky level.
+ * @brief Updates the priority of the thread and makes its home scheduler node
+ *   sticky.
  *
- * @param the_thread The thread.
- * @param sticky_level_change The new value for the sticky level.
+ * @param the_thread is the thread to work on.
  */
-#if defined(RTEMS_SMP)
-void _Thread_Priority_and_sticky_update(
-  Thread_Control *the_thread,
-  int             sticky_level_change
-);
+void _Thread_Priority_update_and_make_sticky( Thread_Control *the_thread );
+
+/**
+ * @brief Updates the priority of the thread and cleans the sticky property of
+ *   its home scheduler node.
+ *
+ * @param the_thread is the thread to work on.
+ */
+void _Thread_Priority_update_and_clean_sticky( Thread_Control *the_thread );
+
+/**
+ * @brief Updates the priority of the thread.
+ *
+ * @param the_thread is the thread to update the priority.
+ */
+void _Thread_Priority_update_ignore_sticky( Thread_Control *the_thread );
 #endif
 
 /**