---
cpukit/include/rtems/score/schedulerimpl.h | 44 +++++++++++++++++-----
1 file changed, 34 insertions(+), 10 deletions(-)
diff --git a/cpukit/include/rtems/score/schedulerimpl.h
b/cpukit/include/rtems/score/schedulerimpl.h
index e7fbb8b166..8f5e1ba7b8 100644
--- a/cpukit/include/rtems/score/schedulerimpl.h
+++ b/cpukit/include/rtems/score/schedulerimpl.h
@@ -929,6 +929,10 @@ RTEMS_INLINE_ROUTINE Thread_Control
*_Scheduler_Use_idle_thread(
return idle;
}
+/**
+ * @brief This enumeration defines what a scheduler should do with a node which
+ * could be scheduled.
+ */
typedef enum {
SCHEDULER_TRY_TO_SCHEDULE_DO_SCHEDULE,
SCHEDULER_TRY_TO_SCHEDULE_DO_IDLE_EXCHANGE,
@@ -936,21 +940,41 @@ typedef enum {
} Scheduler_Try_to_schedule_action;
/**
- * @brief Tries to schedule this scheduler node.
- *
- * @param context The scheduler instance context.
- * @param[in, out] node The node which wants to get scheduled.
- * @param idle A potential idle thread used by a potential victim node.
- * @param get_idle_thread Function to get an idle thread.
- *
- * @retval true This node can be scheduled.
- * @retval false This node cannot be scheduled.
+ * @brief Tries to schedule the scheduler node.
+ *
+ * When a scheduler needs to schedule a node, it shall use this function to
+ * determine what it shall do with the node. The node replaces a victim node
if
+ * it can be scheduled.
+ *
+ * This function uses the state of the node and the scheduler state of the
owner
+ * thread to determine what shall be done. Each scheduler maintains its nodes
+ * independent of other schedulers. This function ensures that a thread is
+ * scheduled by at most one scheduler. If a node requires an executing thread
+ * due to some locking protocol and the owner thread is already scheduled by
+ * another scheduler, then an idle thread shall be attached to the node.
+ *
+ * @param[in, out] context is the scheduler instance context.
+ * @param[in, out] node is the node which could be scheduled.
+ * @param idle is an idle thread used by the victim node or NULL.
+ * @param get_idle_thread points to a function to get an idle thread.
+ *
+ * @retval SCHEDULER_TRY_TO_SCHEDULE_DO_SCHEDULE The node shall be scheduled.
+ *
+ * @retval SCHEDULER_TRY_TO_SCHEDULE_DO_IDLE_EXCHANGE The node shall be
+ * scheduled and the provided idle thread shall be attached to the node.
This
+ * action is returned, if the node cannot use the owner thread and shall use
+ * an idle thread instead. In this case, the idle thread is provided by the
+ * victim node.
+ *
+ * @retval SCHEDULER_TRY_TO_SCHEDULE_DO_BLOCK The node shall be blocked. This
+ * action is returned, if the owner thread is already scheduled by another
+ * scheduler.
*/
RTEMS_INLINE_ROUTINE Scheduler_Try_to_schedule_action
_Scheduler_Try_to_schedule_node(
Scheduler_Context *context,
Scheduler_Node *node,
- Thread_Control *idle,
+ const Thread_Control *idle,
Scheduler_Get_idle_thread get_idle_thread
)
{
--
2.26.2
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