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/**
* @file rtems/score/scheduler.h
*
* @brief Constants and Structures Associated with the Scheduler
*
* This include file contains all the constants and structures associated
* with the scheduler.
*/
/*
* Copyright (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.com/license/LICENSE.
*/
#ifndef _RTEMS_SCORE_SCHEDULER_H
#define _RTEMS_SCORE_SCHEDULER_H
#include <rtems/score/percpu.h>
#include <rtems/score/chain.h>
#include <rtems/score/priority.h>
#include <rtems/score/prioritybitmap.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup ScoreScheduler Scheduler Handler
*
* @ingroup Score
*
* This handler encapsulates functionality related to managing sets of threads
* that are ready for execution.
*/
/**@{*/
/**
* function jump table that holds pointers to the functions that
* implement specific schedulers.
*/
typedef struct {
/** Implements the scheduling decision logic (policy). */
void ( *initialize )(void);
/** Implements the scheduling decision logic (policy). */
void ( *schedule )(void);
/**
* @brief Voluntarily yields the processor per the scheduling policy.
*
* @see _Scheduler_Yield().
*/
void ( *yield )( Thread_Control *thread );
/** Removes the given thread from scheduling decisions. */
void ( *block )(Thread_Control *);
/** Adds the given thread to scheduling decisions. */
void ( *unblock )(Thread_Control *);
/** allocates the scheduler field of the given thread */
void * ( *allocate )(Thread_Control *);
/** frees the scheduler field of the given thread */
void ( *free )(Thread_Control *);
/** updates the scheduler field of the given thread -- primarily used
* when changing the thread's priority. */
void ( *update )(Thread_Control *);
/** enqueue a thread as the last of its priority group */
void ( *enqueue )(Thread_Control *);
/** enqueue a thread as the first of its priority group */
void ( *enqueue_first )(Thread_Control *);
/** extract a thread from the ready set */
void ( *extract )(Thread_Control *);
/**
* Compares two priorities (returns >0 for higher priority, 0 for equal
* and <0 for lower priority).
*/
int ( *priority_compare )(Priority_Control, Priority_Control);
/** This routine is called upon release of a new job. */
void ( *release_job ) (Thread_Control *, uint32_t);
/** perform scheduler update actions required at each clock tick */
void ( *tick )(void);
/**
* @brief Starts the idle thread for a particular processor.
*
* @see _Scheduler_Start_idle().
*/
void ( *start_idle )( Thread_Control *thread, Per_CPU_Control *processor );
} Scheduler_Operations;
/**
* This is the structure used to manage the scheduler.
*/
typedef struct {
/**
* This points to the data structure used to manage the ready set of
* tasks. The pointer varies based upon the type of
* ready queue required by the scheduler.
*/
void *information;
/** The jump table for scheduler-specific functions */
Scheduler_Operations Operations;
} Scheduler_Control;
/**
* The _Scheduler holds the structures used to manage the
* scheduler.
*
* @note Can we make this per-cpu? then _Scheduler will be a macro.
*
* @note This is instantiated and initialized in confdefs.h.
*/
extern Scheduler_Control _Scheduler;
/**
* Macro testing whether @a p1 has lower priority than @a p2
* in the intuitive sense of priority.
*/
#define _Scheduler_Is_priority_lower_than( _p1, _p2 ) \
(_Scheduler_Priority_compare(_p1,_p2) < 0)
/**
* Macro testing whether @a p1 has higher priority than @a p2
* in the intuitive sense of priority.
*/
#define _Scheduler_Is_priority_higher_than( _p1, _p2 ) \
(_Scheduler_Priority_compare(_p1,_p2) > 0)
/**
* @brief Initializes the scheduler to the policy chosen by the user.
*
* This routine initializes the scheduler to the policy chosen by the user
* through confdefs, or to the priority scheduler with ready chains by
* default.
*/
void _Scheduler_Handler_initialization( void );
/**
* @brief Performs tick operations depending on the CPU budget algorithm for
* each executing thread.
*
* This routine is invoked as part of processing each clock tick.
*/
void _Scheduler_default_Tick( void );
/**
* @brief Unblocks the thread.
*
* @param[in,out] thread An idle thread.
* @param[in] processor This parameter is unused.
*/
void _Scheduler_default_Start_idle(
Thread_Control *thread,
Per_CPU_Control *processor
);
#ifndef __RTEMS_APPLICATION__
#include <rtems/score/scheduler.inl>
#endif
/**@}*/
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
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