/**
* @file rtems/score/schedulerpriority.h
*
* @brief Thread Manipulation with the Priority-Based Scheduler
*
* This include file contains all the constants and structures associated
* with the manipulation of threads for the priority-based scheduler.
*/
/*
* Copryight (c) 2010 Gedare Bloom.
* Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#ifndef _RTEMS_SCORE_SCHEDULERPRIORITY_H
#define _RTEMS_SCORE_SCHEDULERPRIORITY_H
#include <rtems/score/chain.h>
#include <rtems/score/prioritybitmap.h>
#include <rtems/score/scheduler.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup ScoreSchedulerDPS Deterministic Priority Scheduler
*
* @ingroup ScoreScheduler
*/
/**@{*/
/**
* Entry points for the Deterministic Priority Based Scheduler.
*/
#define SCHEDULER_PRIORITY_ENTRY_POINTS \
{ \
_Scheduler_priority_Initialize, /* initialize entry point */ \
_Scheduler_priority_Schedule, /* schedule entry point */ \
_Scheduler_priority_Yield, /* yield entry point */ \
_Scheduler_priority_Block, /* block entry point */ \
_Scheduler_priority_Unblock, /* unblock entry point */ \
_Scheduler_priority_Change_priority, /* change priority entry point */ \
SCHEDULER_OPERATION_DEFAULT_ASK_FOR_HELP \
_Scheduler_default_Node_initialize, /* node initialize entry point */ \
_Scheduler_default_Node_destroy, /* node destroy entry point */ \
_Scheduler_priority_Update_priority, /* update priority entry point */ \
_Scheduler_default_Release_job, /* new period of task */ \
_Scheduler_default_Tick, /* tick entry point */ \
_Scheduler_default_Start_idle /* start idle entry point */ \
SCHEDULER_OPERATION_DEFAULT_GET_SET_AFFINITY \
}
typedef struct {
/**
* @brief Basic scheduler context.
*/
Scheduler_Context Base;
/**
* @brief Bit map to indicate non-empty ready queues.
*/
Priority_bit_map_Control Bit_map;
/**
* @brief One ready queue per priority level.
*/
Chain_Control Ready[ 0 ];
} Scheduler_priority_Context;
/**
* @brief Data for ready queue operations.
*/
typedef struct {
/** This field points to the Ready FIFO for this thread's priority. */
Chain_Control *ready_chain;
/** This field contains precalculated priority map indices. */
Priority_bit_map_Information Priority_map;
} Scheduler_priority_Ready_queue;
/**
* @brief Scheduler node specialization for Deterministic Priority schedulers.
*/
typedef struct {
/**
* @brief Basic scheduler node.
*/
Scheduler_Node Base;
/**
* @brief The associated ready queue of this node.
*/
Scheduler_priority_Ready_queue Ready_queue;
} Scheduler_priority_Node;
/**
* @brief Initializes the priority scheduler.
* This routine initializes the priority scheduler.
*/
void _Scheduler_priority_Initialize( const Scheduler_Control *scheduler );
/**
* @brief Removes @a the_thread from the scheduling decision.
*
* This routine removes @a the_thread from the scheduling decision,
* that is, removes it from the ready queue. It performs
* any necessary scheduling operations including the selection of
* a new heir thread.
*
* @param[in] scheduler The scheduler instance.
* @param[in] the_thread is the thread to be blocked
*/
void _Scheduler_priority_Block(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
/**
* @brief Sets the heir thread to be the next ready thread.
*
* This kernel routine sets the heir thread to be the next ready thread
* by invoking the_scheduler->ready_queue->operations->first().
*/
void _Scheduler_priority_Schedule(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
/**
* @brief Updates the scheduler node to reflect the new priority of the
* thread.
*/
void _Scheduler_priority_Update_priority(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Priority_Control new_priority
);
/**
* @brief Add @a the_thread to the scheduling decision.
*
* This routine adds @a the_thread to the scheduling decision,
* that is, adds it to the ready queue and
* updates any appropriate scheduling variables, for example the heir thread.
*
* @param[in] scheduler The scheduler instance.
* @param[in] the_thread will be unblocked
*/
Scheduler_Void_or_thread _Scheduler_priority_Unblock(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
Scheduler_Void_or_thread _Scheduler_priority_Change_priority(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Priority_Control new_priority,
bool prepend_it
);
/**
* @brief The specified THREAD yields.
*
* This routine is invoked when a thread wishes to voluntarily
* transfer control of the processor to another thread in the queue.
*
* This routine will remove the specified THREAD from the ready queue
* and place it immediately at the rear of this chain. Reset timeslice
* and yield the processor functions both use this routine, therefore if
* reset is true and this is the only thread on the queue then the
* timeslice counter is reset. The heir THREAD will be updated if the
* running is also the currently the heir.
*
* - INTERRUPT LATENCY:
* + ready chain
* + select heir
*
* @param[in] scheduler The scheduler instance.
* @param[in,out] the_thread The yielding thread.
*/
Scheduler_Void_or_thread _Scheduler_priority_Yield(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
/**@}*/
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
