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Diffstat (limited to 'cpukit/include/rtems/score/schedulerimpl.h')
| -rw-r--r-- | cpukit/include/rtems/score/schedulerimpl.h | 1203 |
1 files changed, 1203 insertions, 0 deletions
diff --git a/cpukit/include/rtems/score/schedulerimpl.h b/cpukit/include/rtems/score/schedulerimpl.h new file mode 100644 index 0000000000..10c12242a9 --- /dev/null +++ b/cpukit/include/rtems/score/schedulerimpl.h @@ -0,0 +1,1203 @@ +/** + * @file + * + * @brief Inlined Routines Associated with the Manipulation of the Scheduler + * + * This inline file contains all of the inlined routines associated with + * the manipulation of the scheduler. + */ + +/* + * Copyright (C) 2010 Gedare Bloom. + * Copyright (C) 2011 On-Line Applications Research Corporation (OAR). + * Copyright (c) 2014, 2017 embedded brains GmbH + * + * 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_SCHEDULERIMPL_H +#define _RTEMS_SCORE_SCHEDULERIMPL_H + +#include <rtems/score/scheduler.h> +#include <rtems/score/assert.h> +#include <rtems/score/priorityimpl.h> +#include <rtems/score/smpimpl.h> +#include <rtems/score/status.h> +#include <rtems/score/threadimpl.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * @addtogroup ScoreScheduler + */ +/**@{**/ + +/** + * @brief Maps a priority value to support the append indicator. + */ +#define SCHEDULER_PRIORITY_MAP( priority ) ( ( priority ) << 1 ) + +/** + * @brief Returns the plain priority value. + */ +#define SCHEDULER_PRIORITY_UNMAP( priority ) ( ( priority ) >> 1 ) + +/** + * @brief Clears the priority append indicator bit. + */ +#define SCHEDULER_PRIORITY_PURIFY( priority ) \ + ( ( priority ) & ~( (Priority_Control) SCHEDULER_PRIORITY_APPEND_FLAG ) ) + +/** + * @brief Returns the priority control with the append indicator bit set. + */ +#define SCHEDULER_PRIORITY_APPEND( priority ) \ + ( ( priority ) | SCHEDULER_PRIORITY_APPEND_FLAG ) + +/** + * @brief Returns true, if the item should be appended to its priority group, + * otherwise returns false and the item should be prepended to its priority + * group. + */ +#define SCHEDULER_PRIORITY_IS_APPEND( priority ) \ + ( ( ( priority ) & SCHEDULER_PRIORITY_APPEND_FLAG ) != 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 ); + +RTEMS_INLINE_ROUTINE Scheduler_Context *_Scheduler_Get_context( + const Scheduler_Control *scheduler +) +{ + return scheduler->context; +} + +RTEMS_INLINE_ROUTINE const Scheduler_Control *_Scheduler_Get_by_CPU( + const Per_CPU_Control *cpu +) +{ +#if defined(RTEMS_SMP) + return cpu->Scheduler.control; +#else + (void) cpu; + return &_Scheduler_Table[ 0 ]; +#endif +} + +/** + * @brief Acquires the scheduler instance inside a critical section (interrupts + * disabled). + * + * @param[in] scheduler The scheduler instance. + * @param[in] lock_context The lock context to use for + * _Scheduler_Release_critical(). + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Acquire_critical( + const Scheduler_Control *scheduler, + ISR_lock_Context *lock_context +) +{ +#if defined(RTEMS_SMP) + Scheduler_Context *context; + + context = _Scheduler_Get_context( scheduler ); + _ISR_lock_Acquire( &context->Lock, lock_context ); +#else + (void) scheduler; + (void) lock_context; +#endif +} + +/** + * @brief Releases the scheduler instance inside a critical section (interrupts + * disabled). + * + * @param[in] scheduler The scheduler instance. + * @param[in] lock_context The lock context used for + * _Scheduler_Acquire_critical(). + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Release_critical( + const Scheduler_Control *scheduler, + ISR_lock_Context *lock_context +) +{ +#if defined(RTEMS_SMP) + Scheduler_Context *context; + + context = _Scheduler_Get_context( scheduler ); + _ISR_lock_Release( &context->Lock, lock_context ); +#else + (void) scheduler; + (void) lock_context; +#endif +} + +#if defined(RTEMS_SMP) +void _Scheduler_Request_ask_for_help( Thread_Control *the_thread ); + +/** + * @brief Registers an ask for help request if necessary. + * + * The actual ask for help operation is carried out during + * _Thread_Do_dispatch() on a processor related to the thread. This yields a + * better separation of scheduler instances. A thread of one scheduler + * instance should not be forced to carry out too much work for threads on + * other scheduler instances. + * + * @param[in] the_thread The thread in need for help. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Ask_for_help( Thread_Control *the_thread ) +{ + _Assert( _Thread_State_is_owner( the_thread ) ); + + if ( the_thread->Scheduler.helping_nodes > 0 ) { + _Scheduler_Request_ask_for_help( the_thread ); + } +} +#endif + +/** + * The preferred method to add a new scheduler is to define the jump table + * entries and add a case to the _Scheduler_Initialize routine. + * + * Generic scheduling implementations that rely on the ready queue only can + * be found in the _Scheduler_queue_XXX functions. + */ + +/* + * Passing the Scheduler_Control* to these functions allows for multiple + * scheduler's to exist simultaneously, which could be useful on an SMP + * system. Then remote Schedulers may be accessible. How to protect such + * accesses remains an open problem. + */ + +/** + * @brief General scheduling decision. + * + * This kernel routine implements the scheduling decision logic for + * the scheduler. It does NOT dispatch. + * + * @param[in] the_thread The thread which state changed previously. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Schedule( Thread_Control *the_thread ) +{ + const Scheduler_Control *scheduler; + ISR_lock_Context lock_context; + + scheduler = _Thread_Scheduler_get_home( the_thread ); + _Scheduler_Acquire_critical( scheduler, &lock_context ); + + ( *scheduler->Operations.schedule )( scheduler, the_thread ); + + _Scheduler_Release_critical( scheduler, &lock_context ); +} + +/** + * @brief Scheduler yield with a particular thread. + * + * This routine is invoked when a thread wishes to voluntarily transfer control + * of the processor to another thread. + * + * @param[in] the_thread The yielding thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Yield( Thread_Control *the_thread ) +{ + const Scheduler_Control *scheduler; + ISR_lock_Context lock_context; + + scheduler = _Thread_Scheduler_get_home( the_thread ); + _Scheduler_Acquire_critical( scheduler, &lock_context ); + ( *scheduler->Operations.yield )( + scheduler, + the_thread, + _Thread_Scheduler_get_home_node( the_thread ) + ); + _Scheduler_Release_critical( scheduler, &lock_context ); +} + +/** + * @brief Blocks a thread with respect to the scheduler. + * + * This routine removes @a the_thread from the scheduling decision for + * the scheduler. The primary task is to remove the thread from the + * ready queue. It performs any necessary schedulering operations + * including the selection of a new heir thread. + * + * @param[in] the_thread The thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Block( Thread_Control *the_thread ) +{ +#if defined(RTEMS_SMP) + Chain_Node *node; + const Chain_Node *tail; + Scheduler_Node *scheduler_node; + const Scheduler_Control *scheduler; + ISR_lock_Context lock_context; + + node = _Chain_First( &the_thread->Scheduler.Scheduler_nodes ); + tail = _Chain_Immutable_tail( &the_thread->Scheduler.Scheduler_nodes ); + + scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node ); + scheduler = _Scheduler_Node_get_scheduler( scheduler_node ); + + _Scheduler_Acquire_critical( scheduler, &lock_context ); + ( *scheduler->Operations.block )( + scheduler, + the_thread, + scheduler_node + ); + _Scheduler_Release_critical( scheduler, &lock_context ); + + node = _Chain_Next( node ); + + while ( node != tail ) { + scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node ); + scheduler = _Scheduler_Node_get_scheduler( scheduler_node ); + + _Scheduler_Acquire_critical( scheduler, &lock_context ); + ( *scheduler->Operations.withdraw_node )( + scheduler, + the_thread, + scheduler_node, + THREAD_SCHEDULER_BLOCKED + ); + _Scheduler_Release_critical( scheduler, &lock_context ); + + node = _Chain_Next( node ); + } +#else + const Scheduler_Control *scheduler; + + scheduler = _Thread_Scheduler_get_home( the_thread ); + ( *scheduler->Operations.block )( + scheduler, + the_thread, + _Thread_Scheduler_get_home_node( the_thread ) + ); +#endif +} + +/** + * @brief Unblocks a thread with respect to the scheduler. + * + * This operation must fetch the latest thread priority value for this + * scheduler instance and update its internal state if necessary. + * + * @param[in] the_thread The thread. + * + * @see _Scheduler_Node_get_priority(). + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Unblock( Thread_Control *the_thread ) +{ + const Scheduler_Control *scheduler; + ISR_lock_Context lock_context; + + scheduler = _Thread_Scheduler_get_home( the_thread ); + _Scheduler_Acquire_critical( scheduler, &lock_context ); + ( *scheduler->Operations.unblock )( + scheduler, + the_thread, + _Thread_Scheduler_get_home_node( the_thread ) + ); + _Scheduler_Release_critical( scheduler, &lock_context ); +} + +/** + * @brief Propagates a priority change of a thread to the scheduler. + * + * On uni-processor configurations, this operation must evaluate the thread + * state. In case the thread is not ready, then the priority update should be + * deferred to the next scheduler unblock operation. + * + * The operation must update the heir and thread dispatch necessary variables + * in case the set of scheduled threads changes. + * + * @param[in] the_thread The thread changing its priority. + * + * @see _Scheduler_Node_get_priority(). + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Update_priority( Thread_Control *the_thread ) +{ +#if defined(RTEMS_SMP) + Chain_Node *node; + const Chain_Node *tail; + + _Thread_Scheduler_process_requests( the_thread ); + + node = _Chain_First( &the_thread->Scheduler.Scheduler_nodes ); + tail = _Chain_Immutable_tail( &the_thread->Scheduler.Scheduler_nodes ); + + do { + Scheduler_Node *scheduler_node; + const Scheduler_Control *scheduler; + ISR_lock_Context lock_context; + + scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node ); + scheduler = _Scheduler_Node_get_scheduler( scheduler_node ); + + _Scheduler_Acquire_critical( scheduler, &lock_context ); + ( *scheduler->Operations.update_priority )( + scheduler, + the_thread, + scheduler_node + ); + _Scheduler_Release_critical( scheduler, &lock_context ); + + node = _Chain_Next( node ); + } while ( node != tail ); +#else + const Scheduler_Control *scheduler; + + scheduler = _Thread_Scheduler_get_home( the_thread ); + ( *scheduler->Operations.update_priority )( + scheduler, + the_thread, + _Thread_Scheduler_get_home_node( the_thread ) + ); +#endif +} + +#if defined(RTEMS_SMP) +/** + * @brief Changes the sticky level of the home scheduler node and propagates a + * priority change of a thread to the scheduler. + * + * @param[in] the_thread The thread changing its priority or sticky level. + * + * @see _Scheduler_Update_priority(). + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Priority_and_sticky_update( + Thread_Control *the_thread, + int sticky_level_change +) +{ + Chain_Node *node; + const Chain_Node *tail; + Scheduler_Node *scheduler_node; + const Scheduler_Control *scheduler; + ISR_lock_Context lock_context; + + _Thread_Scheduler_process_requests( the_thread ); + + node = _Chain_First( &the_thread->Scheduler.Scheduler_nodes ); + scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node ); + scheduler = _Scheduler_Node_get_scheduler( scheduler_node ); + + _Scheduler_Acquire_critical( scheduler, &lock_context ); + + scheduler_node->sticky_level += sticky_level_change; + _Assert( scheduler_node->sticky_level >= 0 ); + + ( *scheduler->Operations.update_priority )( + scheduler, + the_thread, + scheduler_node + ); + + _Scheduler_Release_critical( scheduler, &lock_context ); + + tail = _Chain_Immutable_tail( &the_thread->Scheduler.Scheduler_nodes ); + node = _Chain_Next( node ); + + while ( node != tail ) { + scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node ); + scheduler = _Scheduler_Node_get_scheduler( scheduler_node ); + + _Scheduler_Acquire_critical( scheduler, &lock_context ); + ( *scheduler->Operations.update_priority )( + scheduler, + the_thread, + scheduler_node + ); + _Scheduler_Release_critical( scheduler, &lock_context ); + + node = _Chain_Next( node ); + } +} +#endif + +/** + * @brief Maps a thread priority from the user domain to the scheduler domain. + * + * Let M be the maximum scheduler priority. The mapping must be bijective in + * the closed interval [0, M], e.g. _Scheduler_Unmap_priority( scheduler, + * _Scheduler_Map_priority( scheduler, p ) ) == p for all p in [0, M]. For + * other values the mapping is undefined. + * + * @param[in] scheduler The scheduler instance. + * @param[in] priority The user domain thread priority. + * + * @return The corresponding thread priority of the scheduler domain is returned. + */ +RTEMS_INLINE_ROUTINE Priority_Control _Scheduler_Map_priority( + const Scheduler_Control *scheduler, + Priority_Control priority +) +{ + return ( *scheduler->Operations.map_priority )( scheduler, priority ); +} + +/** + * @brief Unmaps a thread priority from the scheduler domain to the user domain. + * + * @param[in] scheduler The scheduler instance. + * @param[in] priority The scheduler domain thread priority. + * + * @return The corresponding thread priority of the user domain is returned. + */ +RTEMS_INLINE_ROUTINE Priority_Control _Scheduler_Unmap_priority( + const Scheduler_Control *scheduler, + Priority_Control priority +) +{ + return ( *scheduler->Operations.unmap_priority )( scheduler, priority ); +} + +/** + * @brief Initializes a scheduler node. + * + * The scheduler node contains arbitrary data on function entry. The caller + * must ensure that _Scheduler_Node_destroy() will be called after a + * _Scheduler_Node_initialize() before the memory of the scheduler node is + * destroyed. + * + * @param[in] scheduler The scheduler instance. + * @param[in] node The scheduler node to initialize. + * @param[in] the_thread The thread of the scheduler node to initialize. + * @param[in] priority The thread priority. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Node_initialize( + const Scheduler_Control *scheduler, + Scheduler_Node *node, + Thread_Control *the_thread, + Priority_Control priority +) +{ + ( *scheduler->Operations.node_initialize )( + scheduler, + node, + the_thread, + priority + ); +} + +/** + * @brief Destroys a scheduler node. + * + * The caller must ensure that _Scheduler_Node_destroy() will be called only + * after a corresponding _Scheduler_Node_initialize(). + * + * @param[in] scheduler The scheduler instance. + * @param[in] node The scheduler node to destroy. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Node_destroy( + const Scheduler_Control *scheduler, + Scheduler_Node *node +) +{ + ( *scheduler->Operations.node_destroy )( scheduler, node ); +} + +/** + * @brief Releases a job of a thread with respect to the scheduler. + * + * @param[in] the_thread The thread. + * @param[in] priority_node The priority node of the job. + * @param[in] deadline The deadline in watchdog ticks since boot. + * @param[in] queue_context The thread queue context to provide the set of + * threads for _Thread_Priority_update(). + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Release_job( + Thread_Control *the_thread, + Priority_Node *priority_node, + uint64_t deadline, + Thread_queue_Context *queue_context +) +{ + const Scheduler_Control *scheduler = _Thread_Scheduler_get_home( the_thread ); + + _Thread_queue_Context_clear_priority_updates( queue_context ); + ( *scheduler->Operations.release_job )( + scheduler, + the_thread, + priority_node, + deadline, + queue_context + ); +} + +/** + * @brief Cancels a job of a thread with respect to the scheduler. + * + * @param[in] the_thread The thread. + * @param[in] priority_node The priority node of the job. + * @param[in] queue_context The thread queue context to provide the set of + * threads for _Thread_Priority_update(). + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Cancel_job( + Thread_Control *the_thread, + Priority_Node *priority_node, + Thread_queue_Context *queue_context +) +{ + const Scheduler_Control *scheduler = _Thread_Scheduler_get_home( the_thread ); + + _Thread_queue_Context_clear_priority_updates( queue_context ); + ( *scheduler->Operations.cancel_job )( + scheduler, + the_thread, + priority_node, + queue_context + ); +} + +/** + * @brief Scheduler method invoked at each clock tick. + * + * This method is invoked at each clock tick to allow the scheduler + * implementation to perform any activities required. For the + * scheduler which support standard RTEMS features, this includes + * time-slicing management. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Tick( const Per_CPU_Control *cpu ) +{ + const Scheduler_Control *scheduler = _Scheduler_Get_by_CPU( cpu ); + Thread_Control *executing = cpu->executing; + + if ( scheduler != NULL && executing != NULL ) { + ( *scheduler->Operations.tick )( scheduler, executing ); + } +} + +/** + * @brief Starts the idle thread for a particular processor. + * + * @param[in] scheduler The scheduler instance. + * @param[in,out] the_thread The idle thread for the processor. + * @param[in,out] cpu The processor for the idle thread. + * + * @see _Thread_Create_idle(). + */ +RTEMS_INLINE_ROUTINE void _Scheduler_Start_idle( + const Scheduler_Control *scheduler, + Thread_Control *the_thread, + Per_CPU_Control *cpu +) +{ + ( *scheduler->Operations.start_idle )( scheduler, the_thread, cpu ); +} + +RTEMS_INLINE_ROUTINE bool _Scheduler_Has_processor_ownership( + const Scheduler_Control *scheduler, + uint32_t cpu_index +) +{ +#if defined(RTEMS_SMP) + const Per_CPU_Control *cpu; + const Scheduler_Control *scheduler_of_cpu; + + cpu = _Per_CPU_Get_by_index( cpu_index ); + scheduler_of_cpu = _Scheduler_Get_by_CPU( cpu ); + + return scheduler_of_cpu == scheduler; +#else + (void) scheduler; + (void) cpu_index; + + return true; +#endif +} + +RTEMS_INLINE_ROUTINE const Processor_mask *_Scheduler_Get_processors( + const Scheduler_Control *scheduler +) +{ +#if defined(RTEMS_SMP) + return &_Scheduler_Get_context( scheduler )->Processors; +#else + return &_Processor_mask_The_one_and_only; +#endif +} + +bool _Scheduler_Get_affinity( + Thread_Control *the_thread, + size_t cpusetsize, + cpu_set_t *cpuset +); + +RTEMS_INLINE_ROUTINE bool _Scheduler_default_Set_affinity_body( + const Scheduler_Control *scheduler, + Thread_Control *the_thread, + Scheduler_Node *node, + const Processor_mask *affinity +) +{ + (void) scheduler; + (void) the_thread; + (void) node; + return _Processor_mask_Is_subset( affinity, _SMP_Get_online_processors() ); +} + +bool _Scheduler_Set_affinity( + Thread_Control *the_thread, + size_t cpusetsize, + const cpu_set_t *cpuset +); + +RTEMS_INLINE_ROUTINE void _Scheduler_Generic_block( + const Scheduler_Control *scheduler, + Thread_Control *the_thread, + Scheduler_Node *node, + void ( *extract )( + const Scheduler_Control *, + Thread_Control *, + Scheduler_Node * + ), + void ( *schedule )( + const Scheduler_Control *, + Thread_Control *, + bool + ) +) +{ + ( *extract )( scheduler, the_thread, node ); + + /* TODO: flash critical section? */ + + if ( _Thread_Is_executing( the_thread ) || _Thread_Is_heir( the_thread ) ) { + ( *schedule )( scheduler, the_thread, true ); + } +} + +RTEMS_INLINE_ROUTINE uint32_t _Scheduler_Get_processor_count( + const Scheduler_Control *scheduler +) +{ +#if defined(RTEMS_SMP) + const Scheduler_Context *context = _Scheduler_Get_context( scheduler ); + + return _Processor_mask_Count( &context->Processors ); +#else + (void) scheduler; + + return 1; +#endif +} + +RTEMS_INLINE_ROUTINE Objects_Id _Scheduler_Build_id( uint32_t scheduler_index ) +{ + return _Objects_Build_id( + OBJECTS_FAKE_OBJECTS_API, + OBJECTS_FAKE_OBJECTS_SCHEDULERS, + _Objects_Local_node, + (uint16_t) ( scheduler_index + 1 ) + ); +} + +RTEMS_INLINE_ROUTINE uint32_t _Scheduler_Get_index_by_id( Objects_Id id ) +{ + uint32_t minimum_id = _Scheduler_Build_id( 0 ); + + return id - minimum_id; +} + +RTEMS_INLINE_ROUTINE const Scheduler_Control *_Scheduler_Get_by_id( + Objects_Id id +) +{ + uint32_t index; + + index = _Scheduler_Get_index_by_id( id ); + + if ( index >= _Scheduler_Count ) { + return NULL; + } + + return &_Scheduler_Table[ index ]; +} + +RTEMS_INLINE_ROUTINE uint32_t _Scheduler_Get_index( + const Scheduler_Control *scheduler +) +{ + return (uint32_t) (scheduler - &_Scheduler_Table[ 0 ]); +} + +#if defined(RTEMS_SMP) +/** + * @brief Gets an idle thread from the scheduler instance. + * + * @param[in] context The scheduler instance context. + * + * @retval idle An idle thread for use. This function must always return an + * idle thread. If none is available, then this is a fatal error. + */ +typedef Thread_Control *( *Scheduler_Get_idle_thread )( + Scheduler_Context *context +); + +/** + * @brief Releases an idle thread to the scheduler instance for reuse. + * + * @param[in] context The scheduler instance context. + * @param[in] idle The idle thread to release + */ +typedef void ( *Scheduler_Release_idle_thread )( + Scheduler_Context *context, + Thread_Control *idle +); + +RTEMS_INLINE_ROUTINE void _Scheduler_Thread_change_state( + Thread_Control *the_thread, + Thread_Scheduler_state new_state +) +{ + _Assert( + _ISR_lock_Is_owner( &the_thread->Scheduler.Lock ) + || the_thread->Scheduler.state == THREAD_SCHEDULER_BLOCKED + || !_System_state_Is_up( _System_state_Get() ) + ); + + the_thread->Scheduler.state = new_state; +} + +RTEMS_INLINE_ROUTINE void _Scheduler_Set_idle_thread( + Scheduler_Node *node, + Thread_Control *idle +) +{ + _Assert( _Scheduler_Node_get_idle( node ) == NULL ); + _Assert( + _Scheduler_Node_get_owner( node ) == _Scheduler_Node_get_user( node ) + ); + + _Scheduler_Node_set_user( node, idle ); + node->idle = idle; +} + +/** + * @brief Use an idle thread for this scheduler node. + * + * A thread those home scheduler node has a sticky level greater than zero may + * use an idle thread in the home scheduler instance in case it executes + * currently in another scheduler instance or in case it is in a blocking + * state. + * + * @param[in] context The scheduler instance context. + * @param[in] node The node which wants to use the idle thread. + * @param[in] cpu The processor for the idle thread. + * @param[in] get_idle_thread Function to get an idle thread. + */ +RTEMS_INLINE_ROUTINE Thread_Control *_Scheduler_Use_idle_thread( + Scheduler_Context *context, + Scheduler_Node *node, + Per_CPU_Control *cpu, + Scheduler_Get_idle_thread get_idle_thread +) +{ + Thread_Control *idle = ( *get_idle_thread )( context ); + + _Scheduler_Set_idle_thread( node, idle ); + _Thread_Set_CPU( idle, cpu ); + return idle; +} + +typedef enum { + SCHEDULER_TRY_TO_SCHEDULE_DO_SCHEDULE, + SCHEDULER_TRY_TO_SCHEDULE_DO_IDLE_EXCHANGE, + SCHEDULER_TRY_TO_SCHEDULE_DO_BLOCK +} Scheduler_Try_to_schedule_action; + +/** + * @brief Try to schedule this scheduler node. + * + * @param[in] context The scheduler instance context. + * @param[in] node The node which wants to get scheduled. + * @param[in] idle A potential idle thread used by a potential victim node. + * @param[in] get_idle_thread Function to get an idle thread. + * + * @retval true This node can be scheduled. + * @retval false Otherwise. + */ +RTEMS_INLINE_ROUTINE Scheduler_Try_to_schedule_action +_Scheduler_Try_to_schedule_node( + Scheduler_Context *context, + Scheduler_Node *node, + Thread_Control *idle, + Scheduler_Get_idle_thread get_idle_thread +) +{ + ISR_lock_Context lock_context; + Scheduler_Try_to_schedule_action action; + Thread_Control *owner; + + action = SCHEDULER_TRY_TO_SCHEDULE_DO_SCHEDULE; + owner = _Scheduler_Node_get_owner( node ); + _Assert( _Scheduler_Node_get_user( node ) == owner ); + _Assert( _Scheduler_Node_get_idle( node ) == NULL ); + + _Thread_Scheduler_acquire_critical( owner, &lock_context ); + + if ( owner->Scheduler.state == THREAD_SCHEDULER_READY ) { + _Thread_Scheduler_cancel_need_for_help( owner, _Thread_Get_CPU( owner ) ); + _Scheduler_Thread_change_state( owner, THREAD_SCHEDULER_SCHEDULED ); + } else if ( + owner->Scheduler.state == THREAD_SCHEDULER_SCHEDULED + && node->sticky_level <= 1 + ) { + action = SCHEDULER_TRY_TO_SCHEDULE_DO_BLOCK; + } else if ( node->sticky_level == 0 ) { + action = SCHEDULER_TRY_TO_SCHEDULE_DO_BLOCK; + } else if ( idle != NULL ) { + action = SCHEDULER_TRY_TO_SCHEDULE_DO_IDLE_EXCHANGE; + } else { + _Scheduler_Use_idle_thread( + context, + node, + _Thread_Get_CPU( owner ), + get_idle_thread + ); + } + + _Thread_Scheduler_release_critical( owner, &lock_context ); + return action; +} + +/** + * @brief Release an idle thread using this scheduler node. + * + * @param[in] context The scheduler instance context. + * @param[in] node The node which may have an idle thread as user. + * @param[in] release_idle_thread Function to release an idle thread. + * + * @retval idle The idle thread which used this node. + * @retval NULL This node had no idle thread as an user. + */ +RTEMS_INLINE_ROUTINE Thread_Control *_Scheduler_Release_idle_thread( + Scheduler_Context *context, + Scheduler_Node *node, + Scheduler_Release_idle_thread release_idle_thread +) +{ + Thread_Control *idle = _Scheduler_Node_get_idle( node ); + + if ( idle != NULL ) { + Thread_Control *owner = _Scheduler_Node_get_owner( node ); + + node->idle = NULL; + _Scheduler_Node_set_user( node, owner ); + ( *release_idle_thread )( context, idle ); + } + + return idle; +} + +RTEMS_INLINE_ROUTINE void _Scheduler_Exchange_idle_thread( + Scheduler_Node *needs_idle, + Scheduler_Node *uses_idle, + Thread_Control *idle +) +{ + uses_idle->idle = NULL; + _Scheduler_Node_set_user( + uses_idle, + _Scheduler_Node_get_owner( uses_idle ) + ); + _Scheduler_Set_idle_thread( needs_idle, idle ); +} + +/** + * @brief Block this scheduler node. + * + * @param[in] context The scheduler instance context. + * @param[in] thread The thread which wants to get blocked referencing this + * node. This is not necessarily the user of this node in case the node + * participates in the scheduler helping protocol. + * @param[in] node The node which wants to get blocked. + * @param[in] is_scheduled This node is scheduled. + * @param[in] get_idle_thread Function to get an idle thread. + * + * @retval thread_cpu The processor of the thread. Indicates to continue with + * the blocking operation. + * @retval NULL Otherwise. + */ +RTEMS_INLINE_ROUTINE Per_CPU_Control *_Scheduler_Block_node( + Scheduler_Context *context, + Thread_Control *thread, + Scheduler_Node *node, + bool is_scheduled, + Scheduler_Get_idle_thread get_idle_thread +) +{ + int sticky_level; + ISR_lock_Context lock_context; + Per_CPU_Control *thread_cpu; + + sticky_level = node->sticky_level; + --sticky_level; + node->sticky_level = sticky_level; + _Assert( sticky_level >= 0 ); + + _Thread_Scheduler_acquire_critical( thread, &lock_context ); + thread_cpu = _Thread_Get_CPU( thread ); + _Thread_Scheduler_cancel_need_for_help( thread, thread_cpu ); + _Scheduler_Thread_change_state( thread, THREAD_SCHEDULER_BLOCKED ); + _Thread_Scheduler_release_critical( thread, &lock_context ); + + if ( sticky_level > 0 ) { + if ( is_scheduled && _Scheduler_Node_get_idle( node ) == NULL ) { + Thread_Control *idle; + + idle = _Scheduler_Use_idle_thread( + context, + node, + thread_cpu, + get_idle_thread + ); + _Thread_Dispatch_update_heir( _Per_CPU_Get(), thread_cpu, idle ); + } + + return NULL; + } + + _Assert( thread == _Scheduler_Node_get_user( node ) ); + return thread_cpu; +} + +RTEMS_INLINE_ROUTINE void _Scheduler_Discard_idle_thread( + Scheduler_Context *context, + Thread_Control *the_thread, + Scheduler_Node *node, + Scheduler_Release_idle_thread release_idle_thread +) +{ + Thread_Control *idle; + Thread_Control *owner; + Per_CPU_Control *cpu; + + idle = _Scheduler_Node_get_idle( node ); + owner = _Scheduler_Node_get_owner( node ); + + node->idle = NULL; + _Assert( _Scheduler_Node_get_user( node ) == idle ); + _Scheduler_Node_set_user( node, owner ); + ( *release_idle_thread )( context, idle ); + + cpu = _Thread_Get_CPU( idle ); + _Thread_Set_CPU( the_thread, cpu ); + _Thread_Dispatch_update_heir( _Per_CPU_Get(), cpu, the_thread ); +} + +/** + * @brief Unblock this scheduler node. + * + * @param[in] context The scheduler instance context. + * @param[in] the_thread The thread which wants to get unblocked. + * @param[in] node The node which wants to get unblocked. + * @param[in] is_scheduled This node is scheduled. + * @param[in] release_idle_thread Function to release an idle thread. + * + * @retval true Continue with the unblocking operation. + * @retval false Otherwise. + */ +RTEMS_INLINE_ROUTINE bool _Scheduler_Unblock_node( + Scheduler_Context *context, + Thread_Control *the_thread, + Scheduler_Node *node, + bool is_scheduled, + Scheduler_Release_idle_thread release_idle_thread +) +{ + bool unblock; + + ++node->sticky_level; + _Assert( node->sticky_level > 0 ); + + if ( is_scheduled ) { + _Scheduler_Discard_idle_thread( + context, + the_thread, + node, + release_idle_thread + ); + _Scheduler_Thread_change_state( the_thread, THREAD_SCHEDULER_SCHEDULED ); + unblock = false; + } else { + _Scheduler_Thread_change_state( the_thread, THREAD_SCHEDULER_READY ); + unblock = true; + } + + return unblock; +} +#endif + +RTEMS_INLINE_ROUTINE void _Scheduler_Update_heir( + Thread_Control *new_heir, + bool force_dispatch +) +{ + Thread_Control *heir = _Thread_Heir; + + if ( heir != new_heir && ( heir->is_preemptible || force_dispatch ) ) { +#if defined(RTEMS_SMP) + /* + * We need this state only for _Thread_Get_CPU_time_used(). Cannot use + * _Scheduler_Thread_change_state() since THREAD_SCHEDULER_BLOCKED to + * THREAD_SCHEDULER_BLOCKED state changes are illegal for the real SMP + * schedulers. + */ + heir->Scheduler.state = THREAD_SCHEDULER_BLOCKED; + new_heir->Scheduler.state = THREAD_SCHEDULER_SCHEDULED; +#endif + _Thread_Update_CPU_time_used( heir, _Thread_Get_CPU( heir ) ); + _Thread_Heir = new_heir; + _Thread_Dispatch_necessary = true; + } +} + +RTEMS_INLINE_ROUTINE Status_Control _Scheduler_Set( + const Scheduler_Control *new_scheduler, + Thread_Control *the_thread, + Priority_Control priority +) +{ + Scheduler_Node *new_scheduler_node; + Scheduler_Node *old_scheduler_node; +#if defined(RTEMS_SMP) + ISR_lock_Context lock_context; + const Scheduler_Control *old_scheduler; + +#endif + + if ( the_thread->Wait.queue != NULL ) { + return STATUS_RESOURCE_IN_USE; + } + + old_scheduler_node = _Thread_Scheduler_get_home_node( the_thread ); + _Priority_Plain_extract( + &old_scheduler_node->Wait.Priority, + &the_thread->Real_priority + ); + + if ( !_Priority_Is_empty( &old_scheduler_node->Wait.Priority ) ) { + _Priority_Plain_insert( + &old_scheduler_node->Wait.Priority, + &the_thread->Real_priority, + the_thread->Real_priority.priority + ); + return STATUS_RESOURCE_IN_USE; + } + +#if defined(RTEMS_SMP) + if ( !_Chain_Has_only_one_node( &the_thread->Scheduler.Wait_nodes ) ) { + _Priority_Plain_insert( + &old_scheduler_node->Wait.Priority, + &the_thread->Real_priority, + the_thread->Real_priority.priority + ); + return STATUS_RESOURCE_IN_USE; + } + + old_scheduler = _Thread_Scheduler_get_home( the_thread ); + new_scheduler_node = _Thread_Scheduler_get_node_by_index( + the_thread, + _Scheduler_Get_index( new_scheduler ) + ); + + _Scheduler_Acquire_critical( new_scheduler, &lock_context ); + + if ( + _Scheduler_Get_processor_count( new_scheduler ) == 0 + || !( *new_scheduler->Operations.set_affinity )( + new_scheduler, + the_thread, + new_scheduler_node, + &the_thread->Scheduler.Affinity + ) + ) { + _Scheduler_Release_critical( new_scheduler, &lock_context ); + _Priority_Plain_insert( + &old_scheduler_node->Wait.Priority, + &the_thread->Real_priority, + the_thread->Real_priority.priority + ); + return STATUS_UNSATISFIED; + } + + the_thread->Scheduler.home = new_scheduler; + + _Scheduler_Release_critical( new_scheduler, &lock_context ); + + _Thread_Scheduler_process_requests( the_thread ); +#else + new_scheduler_node = old_scheduler_node; +#endif + + the_thread->Start.initial_priority = priority; + _Priority_Node_set_priority( &the_thread->Real_priority, priority ); + _Priority_Initialize_one( + &new_scheduler_node->Wait.Priority, + &the_thread->Real_priority + ); + +#if defined(RTEMS_SMP) + if ( old_scheduler != new_scheduler ) { + States_Control current_state; + + current_state = the_thread->current_state; + + if ( _States_Is_ready( current_state ) ) { + _Scheduler_Block( the_thread ); + } + + _Assert( old_scheduler_node->sticky_level == 0 ); + _Assert( new_scheduler_node->sticky_level == 0 ); + + _Chain_Extract_unprotected( &old_scheduler_node->Thread.Wait_node ); + _Assert( _Chain_Is_empty( &the_thread->Scheduler.Wait_nodes ) ); + _Chain_Initialize_one( + &the_thread->Scheduler.Wait_nodes, + &new_scheduler_node->Thread.Wait_node + ); + _Chain_Extract_unprotected( + &old_scheduler_node->Thread.Scheduler_node.Chain + ); + _Assert( _Chain_Is_empty( &the_thread->Scheduler.Scheduler_nodes ) ); + _Chain_Initialize_one( + &the_thread->Scheduler.Scheduler_nodes, + &new_scheduler_node->Thread.Scheduler_node.Chain + ); + + _Scheduler_Node_set_priority( new_scheduler_node, priority, false ); + + if ( _States_Is_ready( current_state ) ) { + _Scheduler_Unblock( the_thread ); + } + + return STATUS_SUCCESSFUL; + } +#endif + + _Scheduler_Node_set_priority( new_scheduler_node, priority, false ); + _Scheduler_Update_priority( the_thread ); + return STATUS_SUCCESSFUL; +} + +/** @} */ + +#ifdef __cplusplus +} +#endif + +#endif +/* end of include file */ |