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/**
* @file
*
* @brief Simple SMP Scheduler Implementation
*
* @ingroup ScoreSchedulerSMP
*/
/*
* Copyright (c) 2013 embedded brains GmbH.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/schedulersimplesmp.h>
#include <rtems/score/schedulersimpleimpl.h>
#include <rtems/score/wkspace.h>
static Scheduler_simple_smp_Control *_Scheduler_simple_smp_Instance( void )
{
return _Scheduler.information;
}
void _Scheduler_simple_smp_Initialize( void )
{
Scheduler_simple_smp_Control *self =
_Workspace_Allocate_or_fatal_error( sizeof( *self ) );
_Chain_Initialize_empty( &self->ready );
_Chain_Initialize_empty( &self->scheduled );
_Scheduler.information = self;
}
static void _Scheduler_simple_smp_Allocate_processor(
Thread_Control *scheduled,
Thread_Control *victim
)
{
Per_CPU_Control *cpu_of_scheduled = scheduled->cpu;
Per_CPU_Control *cpu_of_victim = victim->cpu;
Thread_Control *heir;
scheduled->is_scheduled = true;
victim->is_scheduled = false;
if ( scheduled->is_executing ) {
heir = cpu_of_scheduled->heir;
cpu_of_scheduled->heir = scheduled;
} else {
heir = scheduled;
}
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 );
}
}
}
static void _Scheduler_simple_smp_Move_from_scheduled_to_ready(
Chain_Control *ready_chain,
Thread_Control *scheduled_to_ready
)
{
_Chain_Extract_unprotected( &scheduled_to_ready->Object.Node );
_Scheduler_simple_Insert_priority_lifo( ready_chain, scheduled_to_ready );
}
static void _Scheduler_simple_smp_Move_from_ready_to_scheduled(
Chain_Control *scheduled_chain,
Thread_Control *ready_to_scheduled
)
{
_Chain_Extract_unprotected( &ready_to_scheduled->Object.Node );
_Scheduler_simple_Insert_priority_fifo( scheduled_chain, ready_to_scheduled );
}
static void _Scheduler_simple_smp_Insert(
Chain_Control *chain,
Thread_Control *thread,
Chain_Node_order order
)
{
_Chain_Insert_ordered_unprotected( chain, &thread->Object.Node, order );
}
static void _Scheduler_simple_smp_Enqueue_ordered(
Thread_Control *thread,
Chain_Node_order order
)
{
Scheduler_simple_smp_Control *self = _Scheduler_simple_smp_Instance();
/*
* The scheduled chain has exactly processor count nodes after
* initialization, thus the lowest priority scheduled thread exists.
*/
Thread_Control *lowest_scheduled =
(Thread_Control *) _Chain_Last( &self->scheduled );
if ( ( *order )( &thread->Object.Node, &lowest_scheduled->Object.Node ) ) {
_Scheduler_simple_smp_Allocate_processor( thread, lowest_scheduled );
_Scheduler_simple_smp_Insert( &self->scheduled, thread, order );
_Scheduler_simple_smp_Move_from_scheduled_to_ready(
&self->ready,
lowest_scheduled
);
} else {
_Scheduler_simple_smp_Insert( &self->ready, thread, order );
}
}
void _Scheduler_simple_smp_Enqueue_priority_lifo( Thread_Control *thread )
{
_Scheduler_simple_smp_Enqueue_ordered(
thread,
_Scheduler_simple_Insert_priority_lifo_order
);
}
void _Scheduler_simple_smp_Enqueue_priority_fifo( Thread_Control *thread )
{
_Scheduler_simple_smp_Enqueue_ordered(
thread,
_Scheduler_simple_Insert_priority_fifo_order
);
}
void _Scheduler_simple_smp_Extract( Thread_Control *thread )
{
Scheduler_simple_smp_Control *self = _Scheduler_simple_smp_Instance();
_Chain_Extract_unprotected( &thread->Object.Node );
if ( thread->is_scheduled ) {
Thread_Control *highest_ready =
(Thread_Control *) _Chain_First( &self->ready );
_Scheduler_simple_smp_Allocate_processor( highest_ready, thread );
_Scheduler_simple_smp_Move_from_ready_to_scheduled(
&self->scheduled,
highest_ready
);
}
}
void _Scheduler_simple_smp_Yield( Thread_Control *thread )
{
ISR_Level level;
_ISR_Disable( level );
_Scheduler_simple_smp_Extract( thread );
_Scheduler_simple_smp_Enqueue_priority_fifo( thread );
_ISR_Enable( level );
}
void _Scheduler_simple_smp_Schedule( void )
{
/* Nothing to do */
}
void _Scheduler_simple_smp_Start_idle(
Thread_Control *thread,
Per_CPU_Control *cpu
)
{
Scheduler_simple_smp_Control *self = _Scheduler_simple_smp_Instance();
thread->is_scheduled = true;
thread->cpu = cpu;
_Chain_Append_unprotected( &self->scheduled, &thread->Object.Node );
}
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