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/**
* @file rtems/score/scheduler.h
*
* This include file contains all the constants and structures associated
* with the scheduler.
*/
/*
* Copyright (C) 2010 Gedare Bloom.
*
* 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.
*
* $Id$
*/
#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
*
* This handler encapsulates functionality related to managing sets of threads
* that are ready for execution.
*/
/**@{*/
/*
* These defines are used to set the scheduler_policy value. The values
* must correspond directly with the order of the fields in the scheduler
* table (Scheduler_Table_t), because the Configuration.scheduler_policy
* field is used to index the scheduler table.
*/
#define _Scheduler_USER (0)
#define _Scheduler_PRIORITY (1)
typedef struct Scheduler_Control_struct Scheduler_Control;
/*
* The Scheduler_Table_t type defines the scheduler initialization table,
* which is set up by confdefs.h based on the user's choice of scheduler
* policy.
*/
typedef struct {
void ( *scheduler_init )( Scheduler_Control * );
} Scheduler_Table_t;
/* instantiated and initialized in confdefs.h */
extern const Scheduler_Table_t _Scheduler_Table[];
/**
* The following Scheduler_Per_thread_xxx structures are used to
* hold per-thread data used by the scheduler. Thread_Control->scheduler is a
* union of pointers, one for each of the following structures. The
* scheduler->xxx field points to an instantion of one of these structures,
* which is allocated from the workspace during _Thread_Start.
*/
/**
* Per-thread data related to the _Scheduler_PRIORITY scheduling policy.
*/
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_Per_thread;
/**
* function jump table that holds pointers to the functions that
* implement specific schedulers.
*/
typedef struct {
/** Implements the scheduling decision logic (policy). */
void ( *schedule ) ( Scheduler_Control * );
/** Voluntarily yields the processor per the scheduling policy. */
void ( *yield ) ( Scheduler_Control * );
/** Removes the given thread from scheduling decisions. */
void ( *block ) ( Scheduler_Control *, Thread_Control * );
/** Adds the given thread to scheduling decisions. */
void ( *unblock ) ( Scheduler_Control *, Thread_Control * );
/** allocates the scheduler field of the given thread */
void * ( *scheduler_allocate ) ( Scheduler_Control *, Thread_Control * );
/** frees the scheduler field of the given thread */
void ( *scheduler_free ) ( Scheduler_Control *, Thread_Control * );
/** updates the scheduler field of the given thread -- primarily used
* when changing the thread's priority. */
void ( *scheduler_update ) ( Scheduler_Control *, Thread_Control * );
} Scheduler_Operations;
/**
* This is the structure used to manage the scheduler.
*/
struct Scheduler_Control_struct {
/**
* This union contains the pointer 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.
*/
union {
/**
* This is the set of lists (an array of Chain_Control) for
* priority scheduling.
*/
Chain_Control *Priority;
} ready_queues;
/** The jump table for scheduler-specific functions */
Scheduler_Operations operations;
};
/**
* The _Scheduler holds the structures used to manage the
* scheduler.
*
* @note Can we make this per-cpu? then _Scheduler will be a macro.
*/
SCORE_EXTERN Scheduler_Control _Scheduler;
/**
* 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 );
#ifndef __RTEMS_APPLICATION__
#include <rtems/score/scheduler.inl>
#endif
/**@}*/
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
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