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.

2 files changed, 3 insertions, 7 deletions

diff --git a/cpukit/posix/include/rtems/posix/pthreadimpl.h b/cpukit/posix/include/rtems/posix/pthreadimpl.h
index 988246ed53..acf66822c0 100644
--- a/cpukit/posix/include/rtems/posix/pthreadimpl.h
+++ b/cpukit/posix/include/rtems/posix/pthreadimpl.h
@@ -68,6 +68,8 @@ RTEMS_INLINE_ROUTINE void _POSIX_Threads_Sporadic_timer_insert(
   );
 }
 
+void _POSIX_Threads_Sporadic_timer( Watchdog_Control *watchdog );
+
 /**
  * @brief POSIX threads sporadic budget callout.
  *
diff --git a/cpukit/posix/include/rtems/posix/threadsup.h b/cpukit/posix/include/rtems/posix/threadsup.h
index 21977be210..3bb2210d97 100644
--- a/cpukit/posix/include/rtems/posix/threadsup.h
+++ b/cpukit/posix/include/rtems/posix/threadsup.h
@@ -60,13 +60,7 @@ typedef struct {
      * @brief The low priority when using the sporadic server scheduling
      * policy.
      */
-    Priority_Control low_priority;
-
-    /**
-     * @brief The high priority when using the sporadic server scheduling
-     * policy.
-     */
-    Priority_Control high_priority;
+    Priority_Node Low_priority;
   } Sporadic;
 
   /** This is the set of signals which are currently unblocked. */