score: Optimize scheduler priority updates

Thread priority changes may append or prepend the thread to its priority
group on the scheduler ready queue.  Previously, a separate priority
value and a prepend-it flag in the scheduler node were used to propagate
a priority change to the scheduler.

Now, use an append-it bit in the priority control and reduce the plain
priority value to 63 bits.

This change leads to a significant code size reduction (about 25%) of
the SMP schedulers.  The negligible increase of the standard priority
scheduler is due to some additional shift operations
(SCHEDULER_PRIORITY_MAP() and SCHEDULER_PRIORITY_UNMAP()).

Before:

   text filename
    136 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleblock.o
    464 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimplechangepriority.o
     24 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimple.o
    108 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleschedule.o
    292 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleunblock.o
    264 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleyield.o

   text filename
    280 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityblock.o
    488 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerprioritychangepriority.o
    200 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriority.o
    164 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityschedule.o
    328 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityunblock.o
    200 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityyield.o

   text filename
  24112 arm-rtems5/c/imx7/cpukit/score/src/libscore_a-scheduleredfsmp.o

   text filename
  37204 sparc-rtems5/c/gr740/cpukit/score/src/libscore_a-scheduleredfsmp.o

   text filename
  42236 powerpc-rtems5/c/qoriq_e6500_32/cpukit/score/src/libscore_a-scheduleredfsmp.o

After:

   text filename
    136 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleblock.o
    272 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimplechangepriority.o
     24 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimple.o
    108 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleschedule.o
    292 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleunblock.o
    264 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulersimpleyield.o

   text filename
    280 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityblock.o
    488 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerprioritychangepriority.o
    208 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriority.o
    164 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityschedule.o
    332 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityunblock.o
    200 sparc-rtems5/c/erc32/cpukit/score/src/libscore_a-schedulerpriorityyield.o

   text filename
  18860 arm-rtems5/c/imx7/cpukit/score/src/libscore_a-scheduleredfsmp.o

   text filename
  28520 sparc-rtems5/c/gr740/cpukit/score/src/libscore_a-scheduleredfsmp.o

   text filename
  32664 powerpc-rtems5/c/qoriq_e6500_32/cpukit/score/src/libscore_a-scheduleredfsmp.o

1 files changed, 41 insertions, 120 deletions

diff --git a/cpukit/score/src/schedulersimplesmp.c b/cpukit/score/src/schedulersimplesmp.c
index df08a19eab..4ab4987c3a 100644
--- a/cpukit/score/src/schedulersimplesmp.c
+++ b/cpukit/score/src/schedulersimplesmp.c
@@ -99,17 +99,17 @@ static void _Scheduler_simple_SMP_Move_from_scheduled_to_ready(
 )
 {
   Scheduler_simple_SMP_Context *self;
-  Priority_Control              priority_to_insert;
+  Priority_Control              insert_priority;
 
   self = _Scheduler_simple_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( scheduled_to_ready );
 
   _Chain_Extract_unprotected( &scheduled_to_ready->Node.Chain );
+  insert_priority = _Scheduler_SMP_Node_priority( scheduled_to_ready );
   _Chain_Insert_ordered_unprotected(
     &self->Ready,
     &scheduled_to_ready->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_lifo_order
+    &insert_priority,
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
@@ -119,55 +119,36 @@ static void _Scheduler_simple_SMP_Move_from_ready_to_scheduled(
 )
 {
   Scheduler_simple_SMP_Context *self;
-  Priority_Control              priority_to_insert;
+  Priority_Control              insert_priority;
 
   self = _Scheduler_simple_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( ready_to_scheduled );
 
   _Chain_Extract_unprotected( &ready_to_scheduled->Node.Chain );
+  insert_priority = _Scheduler_SMP_Node_priority( ready_to_scheduled );
+  insert_priority = SCHEDULER_PRIORITY_APPEND( insert_priority );
   _Chain_Insert_ordered_unprotected(
     &self->Base.Scheduled,
     &ready_to_scheduled->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_fifo_order
+    &insert_priority,
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
-static void _Scheduler_simple_SMP_Insert_ready_lifo(
+static void _Scheduler_simple_SMP_Insert_ready(
   Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
+  Scheduler_Node    *node_to_insert,
+  Priority_Control   insert_priority
 )
 {
   Scheduler_simple_SMP_Context *self;
-  Priority_Control              priority_to_insert;
 
   self = _Scheduler_simple_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( node_to_insert );
 
   _Chain_Insert_ordered_unprotected(
     &self->Ready,
     &node_to_insert->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_lifo_order
-  );
-}
-
-static void _Scheduler_simple_SMP_Insert_ready_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node_to_insert
-)
-{
-  Scheduler_simple_SMP_Context *self;
-  Priority_Control              priority_to_insert;
-
-  self = _Scheduler_simple_SMP_Get_self( context );
-  priority_to_insert = _Scheduler_SMP_Node_priority( node_to_insert );
-
-  _Chain_Insert_ordered_unprotected(
-    &self->Ready,
-    &node_to_insert->Node.Chain,
-    &priority_to_insert,
-    _Scheduler_SMP_Insert_priority_fifo_order
+    &insert_priority,
+    _Scheduler_SMP_Priority_less_equal
   );
 }
 
@@ -200,103 +181,45 @@ void _Scheduler_simple_SMP_Block(
   );
 }
 
-static bool _Scheduler_simple_SMP_Enqueue_ordered(
-  Scheduler_Context    *context,
-  Scheduler_Node       *node,
-  Chain_Node_order      order,
-  Scheduler_SMP_Insert  insert_ready,
-  Scheduler_SMP_Insert  insert_scheduled
+static bool _Scheduler_simple_SMP_Enqueue(
+  Scheduler_Context *context,
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_ordered(
+  return _Scheduler_SMP_Enqueue(
     context,
     node,
-    order,
-    insert_ready,
-    insert_scheduled,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_simple_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_simple_SMP_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
   );
 }
 
-static bool _Scheduler_simple_SMP_Enqueue_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_simple_SMP_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_simple_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static bool _Scheduler_simple_SMP_Enqueue_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node    *node
-)
-{
-  return _Scheduler_simple_SMP_Enqueue_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_simple_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
-static bool _Scheduler_simple_SMP_Enqueue_scheduled_ordered(
+static bool _Scheduler_simple_SMP_Enqueue_scheduled(
   Scheduler_Context *context,
-  Scheduler_Node *node,
-  Chain_Node_order order,
-  Scheduler_SMP_Insert insert_ready,
-  Scheduler_SMP_Insert insert_scheduled
+  Scheduler_Node    *node,
+  Priority_Control   insert_priority
 )
 {
-  return _Scheduler_SMP_Enqueue_scheduled_ordered(
+  return _Scheduler_SMP_Enqueue_scheduled(
     context,
     node,
-    order,
+    insert_priority,
+    _Scheduler_SMP_Priority_less_equal,
     _Scheduler_simple_SMP_Extract_from_ready,
     _Scheduler_simple_SMP_Get_highest_ready,
-    insert_ready,
-    insert_scheduled,
+    _Scheduler_simple_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_simple_SMP_Move_from_ready_to_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
   );
 }
 
-static bool _Scheduler_simple_SMP_Enqueue_scheduled_lifo(
-  Scheduler_Context *context,
-  Scheduler_Node *node
-)
-{
-  return _Scheduler_simple_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_simple_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo
-  );
-}
-
-static bool _Scheduler_simple_SMP_Enqueue_scheduled_fifo(
-  Scheduler_Context *context,
-  Scheduler_Node *node
-)
-{
-  return _Scheduler_simple_SMP_Enqueue_scheduled_ordered(
-    context,
-    node,
-    _Scheduler_SMP_Insert_priority_fifo_order,
-    _Scheduler_simple_SMP_Insert_ready_fifo,
-    _Scheduler_SMP_Insert_scheduled_fifo
-  );
-}
-
 void _Scheduler_simple_SMP_Unblock(
   const Scheduler_Control *scheduler,
   Thread_Control          *thread,
@@ -310,7 +233,7 @@ void _Scheduler_simple_SMP_Unblock(
     thread,
     node,
     _Scheduler_simple_SMP_Do_update,
-    _Scheduler_simple_SMP_Enqueue_fifo
+    _Scheduler_simple_SMP_Enqueue
   );
 }
 
@@ -324,9 +247,9 @@ static bool _Scheduler_simple_SMP_Do_ask_for_help(
     context,
     the_thread,
     node,
-    _Scheduler_SMP_Insert_priority_lifo_order,
-    _Scheduler_simple_SMP_Insert_ready_lifo,
-    _Scheduler_SMP_Insert_scheduled_lifo,
+    _Scheduler_SMP_Priority_less_equal,
+    _Scheduler_simple_SMP_Insert_ready,
+    _Scheduler_SMP_Insert_scheduled,
     _Scheduler_simple_SMP_Move_from_scheduled_to_ready,
     _Scheduler_SMP_Get_lowest_scheduled,
     _Scheduler_SMP_Allocate_processor_lazy
@@ -347,10 +270,8 @@ void _Scheduler_simple_SMP_Update_priority(
     node,
     _Scheduler_simple_SMP_Extract_from_ready,
     _Scheduler_simple_SMP_Do_update,
-    _Scheduler_simple_SMP_Enqueue_fifo,
-    _Scheduler_simple_SMP_Enqueue_lifo,
-    _Scheduler_simple_SMP_Enqueue_scheduled_fifo,
-    _Scheduler_simple_SMP_Enqueue_scheduled_lifo,
+    _Scheduler_simple_SMP_Enqueue,
+    _Scheduler_simple_SMP_Enqueue_scheduled,
     _Scheduler_simple_SMP_Do_ask_for_help
   );
 }
@@ -414,7 +335,7 @@ void _Scheduler_simple_SMP_Add_processor(
     context,
     idle,
     _Scheduler_simple_SMP_Has_ready,
-    _Scheduler_simple_SMP_Enqueue_scheduled_fifo,
+    _Scheduler_simple_SMP_Enqueue_scheduled,
     _Scheduler_SMP_Do_nothing_register_idle
   );
 }
@@ -430,7 +351,7 @@ Thread_Control *_Scheduler_simple_SMP_Remove_processor(
     context,
     cpu,
     _Scheduler_simple_SMP_Extract_from_ready,
-    _Scheduler_simple_SMP_Enqueue_fifo
+    _Scheduler_simple_SMP_Enqueue
   );
 }
 
@@ -447,7 +368,7 @@ void _Scheduler_simple_SMP_Yield(
     thread,
     node,
     _Scheduler_simple_SMP_Extract_from_ready,
-    _Scheduler_simple_SMP_Enqueue_fifo,
-    _Scheduler_simple_SMP_Enqueue_scheduled_fifo
+    _Scheduler_simple_SMP_Enqueue,
+    _Scheduler_simple_SMP_Enqueue_scheduled
   );
 }