smp: Delete _SMP_Request_other_cores_to_dispatch()

Use an event triggered unicast to inform remote processors about a
necessary thread dispatch instead.

cpukit/score/include/rtems/score/smp.h

@@ -95,14 +95,6 @@ void _SMP_Broadcast_message(
  */
 void _SMP_Request_other_cores_to_perform_first_context_switch(void);
 
-/**
- *  @brief Request dispatch on other cores.
- *
- *  Send message to other cores requesting them to perform
- *  a thread dispatch operation.
- */
-void _SMP_Request_other_cores_to_dispatch(void);
-
 /**
  *  @brief Request other cores to shutdown.
  *

cpukit/score/include/rtems/score/threadimpl.h

@@ -634,8 +634,21 @@ RTEMS_INLINE_ROUTINE uint32_t _Thread_Get_global_exit_status( void )
 
 RTEMS_INLINE_ROUTINE void _Thread_Signal_notification( Thread_Control *thread )
 {
-  if ( _ISR_Is_in_progress() && _Thread_Is_executing( thread ) )
+  if ( _ISR_Is_in_progress() && _Thread_Is_executing( thread ) ) {
     _Thread_Dispatch_necessary = true;
+  } else {
+#if defined(RTEMS_SMP)
+    if ( thread->is_executing ) {
+      const Per_CPU_Control *cpu_of_executing = _Per_CPU_Get();
+      Per_CPU_Control *cpu_of_thread = thread->cpu;
+
+      if ( cpu_of_executing != cpu_of_thread ) {
+        cpu_of_thread->dispatch_necessary = true;
+        _Per_CPU_Send_interrupt( cpu_of_thread );
+      }
+    }
+#endif
+  }
 }
 
 #if !defined(__DYNAMIC_REENT__)

cpukit/score/src/isrsmp.c

@@ -72,8 +72,5 @@ int _ISR_SMP_Exit(void)
 
   _Thread_Dispatch_decrement_disable_level();
 
-   if ( retval == 0 )
-    _SMP_Request_other_cores_to_dispatch();
-
   return retval;
 }

cpukit/score/src/schedulersimplesmp.c

@@ -58,9 +58,15 @@ static void _Scheduler_simple_smp_Allocate_processor(
   }
 
   if ( heir != victim ) {
+    const Per_CPU_Control *cpu_of_executing = _Per_CPU_Get();
+
     heir->cpu = cpu_of_victim;
     cpu_of_victim->heir = heir;
     cpu_of_victim->dispatch_necessary = true;
+
+    if ( cpu_of_victim != cpu_of_executing ) {
+      _Per_CPU_Send_interrupt( cpu_of_victim );
+    }
   }
 }
 

cpukit/score/src/smp.c

@@ -165,27 +165,6 @@ void _SMP_Request_other_cores_to_perform_first_context_switch( void )
   }
 }
 
-void _SMP_Request_other_cores_to_dispatch( void )
-{
-  if ( _System_state_Is_up( _System_state_Get() ) ) {
-    uint32_t self = _SMP_Get_current_processor();
-    uint32_t ncpus = _SMP_Get_processor_count();
-    uint32_t cpu;
-
-    for ( cpu = 0 ; cpu < ncpus ; ++cpu ) {
-      const Per_CPU_Control *per_cpu = &_Per_CPU_Information[ cpu ];
-
-      if (
-        cpu != self
-          && per_cpu->state == PER_CPU_STATE_UP
-          && per_cpu->dispatch_necessary
-      ) {
-        _SMP_Send_message( cpu, 0 );
-      }
-    }
-  }
-}
-
 void _SMP_Request_other_cores_to_shutdown( void )
 {
   uint32_t self = _SMP_Get_current_processor();

cpukit/score/src/threaddispatch.c

@@ -65,11 +65,6 @@ void _Thread_Dispatch( void )
      * once someone calls _Thread_Dispatch().
      */
     _Thread_Disable_dispatch();
-
-    /*
-     *  If necessary, send dispatch request to other cores.
-     */
-    _SMP_Request_other_cores_to_dispatch();
   #else
     _Thread_Dispatch_set_disable_level( 1 );
   #endif

cpukit/score/src/threadinitialize.c

@@ -181,7 +181,9 @@ bool _Thread_Initialize(
 #if defined(RTEMS_SMP)
   the_thread->is_scheduled            = false;
   the_thread->is_executing            = false;
-  the_thread->cpu                     = NULL;
+
+  /* Initialize the cpu field for the non-SMP schedulers */
+  the_thread->cpu                     = _Per_CPU_Get_by_index( 0 );
 #endif
 
   the_thread->current_state           = STATES_DORMANT;