/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSScoreSchedulerStrongAPA
*
* @brief This header file provides the interfaces of the
* @ref RTEMSScoreSchedulerStrongAPA.
*/
/*
* Copyright (C) 2020 Richi Dubey
* Copyright (C) 2013, 2018 embedded brains GmbH & Co. KG
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _RTEMS_SCORE_SCHEDULERSTRONGAPA_H
#define _RTEMS_SCORE_SCHEDULERSTRONGAPA_H
#include <rtems/score/scheduler.h>
#include <rtems/score/schedulersmp.h>
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/* Forward Declaration of Per_CPU_Control */
struct Per_CPU_Control;
/**
* @defgroup RTEMSScoreSchedulerStrongAPA Strong APA Scheduler
*
* @ingroup RTEMSScoreSchedulerSMP
*
* @brief This group contains the Strong APA Scheduler implementation.
*
* This is an implementation of the Strong APA scheduler defined by
* Cerqueira et al. in Linux's Processor Affinity API, Refined:
* Shifting Real-Time Tasks Towards Higher Schedulability.
*
* The scheduled and ready nodes are accessed via the
* Scheduler_strong_APA_Context::Ready which helps in backtracking when a
* node which is executing on a CPU gets blocked. New node is allocated to
* the cpu by checking all the executing nodes in the affinity set of the
* node and the subsequent nodes executing on the processors in its
* affinity set.
* @{
*/
/**
* @brief Scheduler node specialization for Strong APA schedulers.
*/
typedef struct {
/**
* @brief SMP scheduler node.
*/
Scheduler_SMP_Node Base;
/**
* @brief Chain node for Scheduler_strong_APA_Context::Ready.
*/
Chain_Node Ready_node;
/**
* @brief CPU that this node would preempt in the backtracking part of
* _Scheduler_strong_APA_Get_highest_ready and
* _Scheduler_strong_APA_Do_Enqueue.
*/
struct Per_CPU_Control *cpu_to_preempt;
/**
* @brief The associated affinity set of this node.
*/
Processor_mask Affinity;
} Scheduler_strong_APA_Node;
/**
* @brief CPU related variables and a CPU_Control to implement BFS.
*/
typedef struct {
/**
* @brief CPU in a queue.
*/
struct Per_CPU_Control *cpu;
/**
* @brief The node that would preempt this CPU.
*/
Scheduler_Node *preempting_node;
/**
* @brief Whether or not this cpu has been added to the queue
* (visited in BFS).
*/
bool visited;
/**
* @brief The node currently executing on this cpu.
*/
Scheduler_Node *executing;
} Scheduler_strong_APA_CPU;
/**
* @brief Scheduler context and node definition for Strong APA scheduler.
*/
typedef struct {
/**
* @brief @see Scheduler_SMP_Context.
*/
Scheduler_SMP_Context Base;
/**
* @brief Chain of all the ready and scheduled nodes present in
* the Strong APA scheduler.
*/
Chain_Control Ready;
/**
* @brief Stores cpu-specific variables.
*/
Scheduler_strong_APA_CPU CPU[ RTEMS_ZERO_LENGTH_ARRAY ];
} Scheduler_strong_APA_Context;
#define SCHEDULER_STRONG_APA_MAXIMUM_PRIORITY 255
/**
* @brief Entry points for the Strong APA Scheduler.
*/
#define SCHEDULER_STRONG_APA_ENTRY_POINTS \
{ \
_Scheduler_strong_APA_Initialize, \
_Scheduler_default_Schedule, \
_Scheduler_strong_APA_Yield, \
_Scheduler_strong_APA_Block, \
_Scheduler_strong_APA_Unblock, \
_Scheduler_strong_APA_Update_priority, \
_Scheduler_default_Map_priority, \
_Scheduler_default_Unmap_priority, \
_Scheduler_strong_APA_Ask_for_help, \
_Scheduler_strong_APA_Reconsider_help_request, \
_Scheduler_strong_APA_Withdraw_node, \
_Scheduler_strong_APA_Make_sticky, \
_Scheduler_strong_APA_Clean_sticky, \
_Scheduler_default_Pin_or_unpin_not_supported, \
_Scheduler_default_Pin_or_unpin_not_supported, \
_Scheduler_strong_APA_Add_processor, \
_Scheduler_strong_APA_Remove_processor, \
_Scheduler_strong_APA_Node_initialize, \
_Scheduler_default_Node_destroy, \
_Scheduler_default_Release_job, \
_Scheduler_default_Cancel_job, \
_Scheduler_strong_APA_Start_idle, \
_Scheduler_strong_APA_Set_affinity \
}
/**
* @brief Initializes the scheduler.
*
* @param scheduler The scheduler to initialize.
*/
void _Scheduler_strong_APA_Initialize( const Scheduler_Control *scheduler );
/**
* @brief Initializes the node with the given priority.
*
* @param scheduler The scheduler control instance.
* @param[out] node The node to initialize.
* @param the_thread The thread of the node to initialize.
* @param priority The priority for @a node.
*/
void _Scheduler_strong_APA_Node_initialize(
const Scheduler_Control *scheduler,
Scheduler_Node *node,
Thread_Control *the_thread,
Priority_Control priority
);
/**
* @brief Blocks the thread.
*
* @param scheduler The scheduler control instance.
* @param[in, out] the_thread The thread to block.
* @param[in, out] node The node of the thread to block.
*/
void _Scheduler_strong_APA_Block(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Unblocks the thread.
*
* @param scheduler The scheduler control instance.
* @param[in, out] the_thread The thread to unblock.
* @param[in, out] node The node of the thread to unblock.
*/
void _Scheduler_strong_APA_Unblock(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Updates the priority of the node.
*
* @param scheduler The scheduler control instance.
* @param the_thread The thread for the operation.
* @param[in, out] node The node to update the priority of.
*/
void _Scheduler_strong_APA_Update_priority(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Asks for help.
*
* @param scheduler The scheduler control instance.
* @param the_thread The thread that asks for help.
* @param node The node of @a the_thread.
*
* @retval true The request for help was successful.
* @retval false The request for help was not successful.
*/
bool _Scheduler_strong_APA_Ask_for_help(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Reconsiders help request.
*
* @param scheduler The scheduler control instance.
* @param the_thread The thread to reconsider the help request of.
* @param[in, out] node The node of @a the_thread
*/
void _Scheduler_strong_APA_Reconsider_help_request(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Withdraws the node.
*
* @param scheduler The scheduler control instance.
* @param[in, out] the_thread The thread to change the state to @a next_state.
* @param[in, out] node The node to withdraw.
* @param next_state The next state for @a the_thread.
*/
void _Scheduler_strong_APA_Withdraw_node(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node,
Thread_Scheduler_state next_state
);
/**
* @brief Makes the node sticky.
*
* @param scheduler is the scheduler of the node.
*
* @param[in, out] the_thread is the thread owning the node.
*
* @param[in, out] node is the scheduler node to make sticky.
*/
void _Scheduler_strong_APA_Make_sticky(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Cleans the sticky property from the node.
*
* @param scheduler is the scheduler of the node.
*
* @param[in, out] the_thread is the thread owning the node.
*
* @param[in, out] node is the scheduler node to clean the sticky property.
*/
void _Scheduler_strong_APA_Clean_sticky(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Makes the node sticky.
*
* @param scheduler is the scheduler of the node.
*
* @param[in, out] the_thread is the thread owning the node.
*
* @param[in, out] node is the scheduler node to make sticky.
*/
void _Scheduler_strong_APA_Make_sticky(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Cleans the sticky property from the node.
*
* @param scheduler is the scheduler of the node.
*
* @param[in, out] the_thread is the thread owning the node.
*
* @param[in, out] node is the scheduler node to clean the sticky property.
*/
void _Scheduler_strong_APA_sticky(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Adds the idle thread to a processor.
*
* @param scheduler The scheduler control instance.
* @param[in, out] The idle thread to add to the processor.
*/
void _Scheduler_strong_APA_Add_processor(
const Scheduler_Control *scheduler,
Thread_Control *idle
);
/**
* @brief Removes an idle thread from the given cpu.
*
* @param scheduler The scheduler instance.
* @param cpu The cpu control to remove from @a scheduler.
*
* @return The idle thread of the processor.
*/
Thread_Control *_Scheduler_strong_APA_Remove_processor(
const Scheduler_Control *scheduler,
struct Per_CPU_Control *cpu
);
/**
* @brief Performs a yield operation.
*
* @param scheduler The scheduler control instance.
* @param the_thread The thread to yield.
* @param[in, out] node The node of @a the_thread.
*/
void _Scheduler_strong_APA_Yield(
const Scheduler_Control *scheduler,
Thread_Control *the_thread,
Scheduler_Node *node
);
/**
* @brief Starts an idle thread.
*
* @param scheduler The scheduler instance.
* @param[in, out] the_thread An idle thread.
* @param cpu The cpu for the operation.
*/
void _Scheduler_strong_APA_Start_idle(
const Scheduler_Control *scheduler,
Thread_Control *idle,
struct Per_CPU_Control *cpu
);
/**
* @brief Sets the affinity .
*
* @param scheduler The scheduler control instance.
* @param the_thread The thread to yield.
* @param[in, out] node The node of @a the_thread.
*/
Status_Control _Scheduler_strong_APA_Set_affinity(
const Scheduler_Control *scheduler,
Thread_Control *thread,
Scheduler_Node *node_base,
const Processor_mask *affinity
);
/** @} */
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* _RTEMS_SCORE_SCHEDULERSTRONGAPA_H */
