From 300f6a481aaf9e6d29811faca71bf7104a01492c Mon Sep 17 00:00:00 2001
From: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date: Wed, 22 Jun 2016 17:09:23 +0200
Subject: score: Rework thread priority management

Add priority nodes which contribute to the overall thread priority.

The actual priority of a thread is now an aggregation of priority nodes.
The thread priority aggregation for the home scheduler instance of a
thread consists of at least one priority node, which is normally the
real priority of the thread.  The locking protocols (e.g. priority
ceiling and priority inheritance), rate-monotonic period objects and the
POSIX sporadic server add, change and remove priority nodes.

A thread changes its priority now immediately, e.g. priority changes are
not deferred until the thread releases its last resource.

Replace the _Thread_Change_priority() function with

 * _Thread_Priority_perform_actions(),
 * _Thread_Priority_add(),
 * _Thread_Priority_remove(),
 * _Thread_Priority_change(), and
 * _Thread_Priority_update().

Update #2412.
Update #2556.
---
 cpukit/score/src/threadrestart.c | 61 ++++++++++++++++++----------------------
 1 file changed, 27 insertions(+), 34 deletions(-)

(limited to 'cpukit/score/src/threadrestart.c')

diff --git a/cpukit/score/src/threadrestart.c b/cpukit/score/src/threadrestart.c
index 149882795c..69534001aa 100644
--- a/cpukit/score/src/threadrestart.c
+++ b/cpukit/score/src/threadrestart.c
@@ -50,40 +50,28 @@ static Thread_Zombie_control _Thread_Zombies = {
   .Lock = ISR_LOCK_INITIALIZER( "thread zombies" )
 };
 
-static bool _Thread_Raise_real_priority_filter(
+static void _Thread_Raise_real_priority(
   Thread_Control   *the_thread,
-  Priority_Control *new_priority_ptr,
-  void             *arg
+  Priority_Control  priority
 )
 {
-  Priority_Control real_priority;
-  Priority_Control new_priority;
-  Priority_Control current_priority;
-
-  real_priority = the_thread->real_priority;
-  new_priority = *new_priority_ptr;
-  current_priority = _Thread_Get_priority( the_thread );
-
-  new_priority = _Thread_Priority_highest( real_priority, new_priority );
-  *new_priority_ptr = new_priority;
+  Thread_queue_Context queue_context;
 
-  the_thread->real_priority = new_priority;
+  _Thread_queue_Context_clear_priority_updates( &queue_context );
+  _Thread_Wait_acquire( the_thread, &queue_context );
 
-  return _Thread_Priority_less_than( current_priority, new_priority );
-}
+  if ( priority < the_thread->Real_priority.priority ) {
+    _Thread_Priority_change(
+      the_thread,
+      &the_thread->Real_priority,
+      priority,
+      false,
+      &queue_context
+    );
+  }
 
-static void _Thread_Raise_real_priority(
-  Thread_Control   *the_thread,
-  Priority_Control  priority
-)
-{
-  _Thread_Change_priority(
-    the_thread,
-    priority,
-    NULL,
-    _Thread_Raise_real_priority_filter,
-    false
-  );
+  _Thread_Wait_release( the_thread, &queue_context );
+  _Thread_Priority_update( &queue_context );
 }
 
 typedef struct {
@@ -182,7 +170,7 @@ static void _Thread_Free( Thread_Control *the_thread )
   _ISR_lock_Destroy( &the_thread->Keys.Lock );
   _Scheduler_Node_destroy(
     _Scheduler_Get( the_thread ),
-    _Scheduler_Thread_get_own_node( the_thread )
+    _Thread_Scheduler_get_own_node( the_thread )
   );
   _ISR_lock_Destroy( &the_thread->Timer.Lock );
 
@@ -622,8 +610,8 @@ void _Thread_Restart_self(
   ISR_lock_Context               *lock_context
 )
 {
-  Per_CPU_Control  *cpu_self;
-  Priority_Control  unused;
+  Per_CPU_Control      *cpu_self;
+  Thread_queue_Context  queue_context;
 
   _Assert(
     _Watchdog_Get_state( &executing->Timer.Watchdog ) == WATCHDOG_INACTIVE
@@ -646,13 +634,18 @@ void _Thread_Restart_self(
   cpu_self = _Thread_Dispatch_disable_critical( lock_context );
   _Thread_State_release( executing, lock_context );
 
-  _Thread_Set_priority(
+  _Thread_queue_Context_clear_priority_updates( &queue_context );
+  _Thread_Wait_acquire_default( executing, lock_context );
+  _Thread_Priority_change(
     executing,
+    &executing->Real_priority,
     executing->Start.initial_priority,
-    &unused,
-    true
+    false,
+    &queue_context
   );
+  _Thread_Wait_release_default( executing, lock_context );
 
+  _Thread_Priority_update( &queue_context );
   _Thread_Dispatch_enable( cpu_self );
   RTEMS_UNREACHABLE();
 }
-- 
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