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.

1 files changed, 0 insertions, 34 deletions

diff --git a/cpukit/score/src/scheduleredfextract.c b/cpukit/score/src/scheduleredfextract.c
deleted file mode 100644
index 94fde0a05c..0000000000
--- a/cpukit/score/src/scheduleredfextract.c
+++ /dev/null
@@ -1,34 +0,0 @@
-/**
- *  @file
- *
- *  @brief Scheduler EDF Extract
- *  @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_Extract(
-  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_Extract( &context->Ready, &node->Node );
-  node->queue_state = SCHEDULER_EDF_QUEUE_STATE_NOT_PRESENTLY;
-}