/**
* @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.org/license/LICENSE.
*/
#ifndef _RTEMS_SCORE_SCHEDULER_H
#define _RTEMS_SCORE_SCHEDULER_H
#include <rtems/score/percpu.h>
#include <rtems/score/priority.h>
#include <rtems/score/thread.h>
#if defined(__RTEMS_HAVE_SYS_CPUSET_H__) && defined(RTEMS_SMP)
#include <sys/cpuset.h>
#endif
#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.
*/
/**@{*/
typedef struct Scheduler_Control Scheduler_Control;
/**
* function jump table that holds pointers to the functions that
* implement specific schedulers.
*/
typedef struct {
/** Implements the scheduling decision logic (policy). */
void ( *initialize )( const Scheduler_Control * );
/** Implements the scheduling decision logic (policy). */
void ( *schedule )( const Scheduler_Control *, Thread_Control *);
/**
* @brief Voluntarily yields the processor per the scheduling policy.
*
* @see _Scheduler_Yield().
*/
void ( *yield )( const Scheduler_Control *, Thread_Control *);
/** Removes the given thread from scheduling decisions. */
void ( *block )( const Scheduler_Control *, Thread_Control * );
/** Adds the given thread to scheduling decisions. */
void ( *unblock )( const Scheduler_Control *, Thread_Control * );
/** allocates the scheduler field of the given thread */
bool ( *allocate )( const Scheduler_Control *, Thread_Control * );
/** frees the scheduler field of the given thread */
void ( *free )( const Scheduler_Control *, Thread_Control * );
/** updates the scheduler field of the given thread -- primarily used
* when changing the thread's priority. */
void ( *update )( const Scheduler_Control *, Thread_Control * );
/** enqueue a thread as the last of its priority group */
void ( *enqueue )( const Scheduler_Control *, Thread_Control * );
/** enqueue a thread as the first of its priority group */
void ( *enqueue_first )( const Scheduler_Control *, Thread_Control * );
/** extract a thread from the ready set */
void ( *extract )( const Scheduler_Control *, 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 ) (
const Scheduler_Control *,
Thread_Control *,
uint32_t
);
/** perform scheduler update actions required at each clock tick */
void ( *tick )( const Scheduler_Control * );
/**
* @brief Starts the idle thread for a particular processor.
*
* @see _Scheduler_Start_idle().
*/
void ( *start_idle )(
const Scheduler_Control *,
Thread_Control *,
Per_CPU_Control *
);
#if defined(__RTEMS_HAVE_SYS_CPUSET_H__) && defined(RTEMS_SMP)
/**
* @brief Obtain the processor affinity for a thread.
*
* @see _Scheduler_Get_affinity().
*/
bool ( *get_affinity )(
const Scheduler_Control *,
Thread_Control *,
size_t,
cpu_set_t *
);
/**
* @brief Set the processor affinity for a thread.
*
* @see _Scheduler_Set_affinity().
*/
bool ( *set_affinity )(
const Scheduler_Control *,
Thread_Control *,
size_t,
const cpu_set_t *
);
#endif
} Scheduler_Operations;
/**
* @brief Scheduler context.
*
* The scheduler context of a particular scheduler implementation must place
* this structure at the begin of its context structure.
*/
typedef struct {
/* No fields yet */
} Scheduler_Context;
/**
* @brief Scheduler control.
*/
struct Scheduler_Control {
/**
* @brief Reference to a statically allocated scheduler context.
*/
Scheduler_Context *context;
/**
* @brief The scheduler operations.
*/
Scheduler_Operations Operations;
/**
* @brief The scheduler name.
*/
uint32_t name;
};
/**
* @brief Registered schedulers.
*
* Application provided via <rtems/confdefs.h>.
*
* @see _Scheduler_Count.
*/
extern const Scheduler_Control _Scheduler_Table[];
/**
* @brief Count of registered schedulers.
*
* Application provided via <rtems/confdefs.h> on SMP configurations.
*
* It is very important that this is a compile-time constant on uni-processor
* configurations (in this case RTEMS_SMP is not defined) so that the compiler
* can optimize the some loops away
*
* @see _Scheduler_Table.
*/
#if defined(RTEMS_SMP)
extern const size_t _Scheduler_Count;
#else
#define _Scheduler_Count ( (size_t) 1 )
#endif
/**
* @brief Returns an arbitrary non-NULL value.
*
* @param[in] scheduler Unused.
* @param[in] the_thread Unused.
*
* @retval true Always.
*/
bool _Scheduler_default_Allocate(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
/**
* @brief Does nothing.
*
* @param[in] scheduler Unused.
* @param[in] the_thread Unused.
*/
void _Scheduler_default_Free(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
/**
* @brief Does nothing.
*
* @param[in] scheduler Unused.
* @param[in] the_thread Unused.
*/
void _Scheduler_default_Update(
const Scheduler_Control *scheduler,
Thread_Control *the_thread
);
/**
* @brief Does nothing.
*
* @param[in] scheduler Unused.
* @param[in] the_thread Unused.
* @param[in] deadline Unused.
*/
void _Scheduler_default_Release_job(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
uint32_t deadline
);
/**
* @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.
*
* @param[in] scheduler The scheduler.
*/
void _Scheduler_default_Tick( const Scheduler_Control *scheduler );
/**
* @brief Starts an idle thread.
*
* @param[in] scheduler The scheduler.
* @param[in] the_thread An idle thread.
* @param[in] cpu This parameter is unused.
*/
void _Scheduler_default_Start_idle(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Per_CPU_Control *cpu
);
#if defined(__RTEMS_HAVE_SYS_CPUSET_H__) && defined(RTEMS_SMP)
/**
* @brief Get affinity for the default scheduler.
*
* @param[in] thread The associated thread.
* @param[in] cpusetsize The size of the cpuset.
* @param[out] cpuset Affinity set containing all CPUs.
*
* @retval 0 Successfully got cpuset
* @retval -1 The cpusetsize is invalid for the system
*/
bool _Scheduler_default_Get_affinity(
const Scheduler_Control *scheduler,
Thread_Control *thread,
size_t cpusetsize,
cpu_set_t *cpuset
);
/**
* @brief Set affinity for the default scheduler.
*
* @param[in] thread The associated thread.
* @param[in] cpusetsize The size of the cpuset.
* @param[in] cpuset Affinity new affinity set.
*
* @retval 0 Successful
*
* This method always returns successful and does not save
* the cpuset.
*/
bool _Scheduler_default_Set_affinity(
const Scheduler_Control *scheduler,
Thread_Control *thread,
size_t cpusetsize,
const cpu_set_t *cpuset
);
#endif
/*
* See also PR2174: Memory corruption with EDF scheduler and thread priority
* queues.
*/
extern const bool _Scheduler_FIXME_thread_priority_queues_are_broken;
/**@}*/
#ifdef __cplusplus
}
#endif
#endif
/* end of include file */
