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/*
* Copyright (c) 2014, 2016 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Dornierstr. 4
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* 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_SCHEDULERNODE_H
#define _RTEMS_SCORE_SCHEDULERNODE_H
#include <rtems/score/basedefs.h>
#include <rtems/score/chain.h>
#include <rtems/score/priority.h>
#include <rtems/score/smplockseq.h>
struct _Thread_Control;
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
#if defined(RTEMS_SMP)
/**
* @brief The scheduler node requests.
*/
typedef enum {
/**
* @brief The scheduler node is not on the list of pending requests.
*/
SCHEDULER_NODE_REQUEST_NOT_PENDING,
/**
* @brief There is a pending scheduler node request to add this scheduler
* node to the Thread_Control::Scheduler::Scheduler_nodes chain.
*/
SCHEDULER_NODE_REQUEST_ADD,
/**
* @brief There is a pending scheduler node request to remove this scheduler
* node from the Thread_Control::Scheduler::Scheduler_nodes chain.
*/
SCHEDULER_NODE_REQUEST_REMOVE,
/**
* @brief The scheduler node is on the list of pending requests, but nothing
* should change.
*/
SCHEDULER_NODE_REQUEST_NOTHING,
} Scheduler_Node_request;
#endif
typedef struct Scheduler_Node Scheduler_Node;
/**
* @brief Scheduler node for per-thread data.
*/
struct Scheduler_Node {
#if defined(RTEMS_SMP)
/**
* @brief Chain node for usage in various scheduler data structures.
*
* Strictly, this is the wrong place for this field since the data structures
* to manage scheduler nodes belong to the particular scheduler
* implementation. Currently, all SMP scheduler implementations use chains
* or red-black trees. The node is here to simplify things, just like the
* object node in the thread control block.
*/
union {
Chain_Node Chain;
RBTree_Node RBTree;
} Node;
/**
* @brief The sticky level determines if this scheduler node should use an
* idle thread in case this node is scheduled and the owner thread is
* blocked.
*/
int sticky_level;
/**
* @brief The thread using this node.
*
* This is either the owner or an idle thread.
*/
struct _Thread_Control *user;
/**
* @brief The idle thread claimed by this node in case the sticky level is
* greater than zero and the thread is block or is scheduled on another
* scheduler instance.
*
* This is necessary to ensure the priority ceiling protocols work across
* scheduler boundaries.
*/
struct _Thread_Control *idle;
#endif
/**
* @brief The thread owning this node.
*/
struct _Thread_Control *owner;
#if defined(RTEMS_SMP)
/**
* @brief Block to register and manage this scheduler node in the thread
* control block of the owner of this scheduler node.
*/
struct {
/**
* @brief Node to add this scheduler node to
* Thread_Control::Scheduler::Wait_nodes.
*/
Chain_Node Wait_node;
/**
* @brief Node to add this scheduler node to
* Thread_Control::Scheduler::Scheduler_nodes or a temporary remove list.
*/
union {
/**
* @brief The node for Thread_Control::Scheduler::Scheduler_nodes.
*/
Chain_Node Chain;
/**
* @brief The next pointer for a temporary remove list.
*
* @see _Thread_Scheduler_process_requests().
*/
Scheduler_Node *next;
} Scheduler_node;
/**
* @brief Link to the next scheduler node in the
* Thread_Control::Scheduler::requests list.
*/
Scheduler_Node *next_request;
/**
* @brief The current scheduler node request.
*/
Scheduler_Node_request request;
} Thread;
#endif
/**
* @brief Thread wait support block.
*/
struct {
Priority_Aggregation Priority;
} Wait;
/**
* @brief The thread priority information used by the scheduler.
*
* The thread priority is manifest in two independent areas. One area is the
* user visible thread priority along with a potential thread queue. The
* other is the scheduler. During a thread priority change, the user visible
* thread priority and the thread queue are first updated and the thread
* priority value here is changed. Once this is done the scheduler is
* notified via the update priority operation, so that it can update its
* internal state and honour a new thread priority value.
*/
struct {
/**
* @brief The thread priority value of this scheduler node.
*
* The producer of this value is _Thread_Change_priority(). The consumer
* is the scheduler via the unblock and update priority operations.
*
* This priority control consists of two parts. One part is the plain
* priority value (most-significant 63 bits). The other part is the
* least-significant bit which indicates if the thread should be appended
* (bit set) or prepended (bit cleared) to its priority group, see
* SCHEDULER_PRIORITY_APPEND().
*/
Priority_Control value;
#if defined(RTEMS_SMP)
/**
* @brief Sequence lock to synchronize priority value updates.
*/
SMP_sequence_lock_Control Lock;
#endif
} Priority;
};
#if defined(RTEMS_SMP)
/**
* @brief The size of a scheduler node.
*
* This value is provided via <rtems/confdefs.h>.
*/
extern const size_t _Scheduler_Node_size;
#endif
#if defined(RTEMS_SMP)
#define SCHEDULER_NODE_OF_THREAD_WAIT_NODE( node ) \
RTEMS_CONTAINER_OF( node, Scheduler_Node, Thread.Wait_node )
#define SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node ) \
RTEMS_CONTAINER_OF( node, Scheduler_Node, Thread.Scheduler_node.Chain )
#endif
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* _RTEMS_SCORE_SCHEDULERNODE_H */
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