schedulerimpl.h

Go to the documentation of this file.

/* SPDX-License-Identifier: BSD-2-Clause */
 
/*
 *  Copyright (C) 2010 Gedare Bloom.
 *  Copyright (C) 2011 On-Line Applications Research Corporation (OAR).
 *  Copyright (C) 2014, 2017 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_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
 
void _Scheduler_Handler_initialization( void );
 
static inline Scheduler_Context *_Scheduler_Get_context(
  const Scheduler_Control *scheduler
)
{
  return scheduler->context;
}
 
static inline 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
}
 
static inline 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
}
 
static inline 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)
static inline bool _Scheduler_Is_non_preempt_mode_supported(
  const Scheduler_Control *scheduler
)
{
  return scheduler->is_non_preempt_mode_supported;
}
#endif
 
/*
 * 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.
 */
 
static inline 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 );
}
 
static inline 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 );
}
 
static inline 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
}
 
static inline void _Scheduler_Unblock( Thread_Control *the_thread )
{
  Scheduler_Node          *scheduler_node;
  const Scheduler_Control *scheduler;
  ISR_lock_Context         lock_context;
 
#if defined(RTEMS_SMP)
  scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE(
    _Chain_First( &the_thread->Scheduler.Scheduler_nodes )
  );
  scheduler = _Scheduler_Node_get_scheduler( scheduler_node );
#else
  scheduler_node = _Thread_Scheduler_get_home_node( the_thread );
  scheduler = _Thread_Scheduler_get_home( the_thread );
#endif
 
  _Scheduler_Acquire_critical( scheduler, &lock_context );
  ( *scheduler->Operations.unblock )( scheduler, the_thread, scheduler_node );
  _Scheduler_Release_critical( scheduler, &lock_context );
}
 
static inline 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
}
 
static inline Priority_Control _Scheduler_Map_priority(
  const Scheduler_Control *scheduler,
  Priority_Control         priority
)
{
  return ( *scheduler->Operations.map_priority )( scheduler, priority );
}
 
static inline Priority_Control _Scheduler_Unmap_priority(
  const Scheduler_Control *scheduler,
  Priority_Control         priority
)
{
  return ( *scheduler->Operations.unmap_priority )( scheduler, priority );
}
 
static inline 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
  );
}
 
static inline void _Scheduler_Node_destroy(
  const Scheduler_Control *scheduler,
  Scheduler_Node          *node
)
{
  ( *scheduler->Operations.node_destroy )( scheduler, node );
}
 
static inline 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
  );
}
 
static inline 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
  );
}
 
static inline void _Scheduler_Start_idle(
  const Scheduler_Control *scheduler,
  Thread_Control          *the_thread,
  Per_CPU_Control         *cpu
)
{
  ( *scheduler->Operations.start_idle )( scheduler, the_thread, cpu );
}
 
static inline 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
}
 
static inline 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
}
 
Status_Control _Scheduler_Get_affinity(
  Thread_Control *the_thread,
  size_t          cpusetsize,
  cpu_set_t      *cpuset
);
 
static inline Status_Control _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;
 
  if ( !_Processor_mask_Is_subset( affinity, _SMP_Get_online_processors() ) ) {
    return STATUS_INVALID_NUMBER;
  }
 
  return STATUS_SUCCESSFUL;
}
 
Status_Control _Scheduler_Set_affinity(
  Thread_Control  *the_thread,
  size_t           cpusetsize,
  const cpu_set_t *cpuset
);
 
static inline 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
}
 
static inline 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 )
  );
}
 
static inline uint32_t _Scheduler_Get_index_by_id( Objects_Id id )
{
  uint32_t minimum_id = _Scheduler_Build_id( 0 );
 
  return id - minimum_id;
}
 
static inline 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 ];
}
 
static inline uint32_t _Scheduler_Get_index(
  const Scheduler_Control *scheduler
)
{
  return (uint32_t) (scheduler - &_Scheduler_Table[ 0 ]);
}
 
#if defined(RTEMS_SMP)
typedef Scheduler_Node *( *Scheduler_Get_idle_node )( void *arg );
 
typedef void ( *Scheduler_Release_idle_node )(
  Scheduler_Node *node,
  void           *arg
);
 
static inline 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;
}
 
static inline Thread_Control *_Scheduler_Use_idle_thread(
  Scheduler_Node          *node,
  Scheduler_Get_idle_node  get_idle_node,
  void                    *arg
)
{
  Scheduler_Node *idle_node;
  Thread_Control *idle;
 
  idle_node = ( *get_idle_node )( arg );
  idle = _Scheduler_Node_get_owner( idle_node );
  _Assert( idle->is_idle );
  _Scheduler_Node_set_idle_user( node, idle );
 
  return idle;
}
 
static inline void _Scheduler_Release_idle_thread(
  Scheduler_Node             *node,
  const Thread_Control       *idle,
  Scheduler_Release_idle_node release_idle_node,
  void                       *arg
)
{
  Thread_Control *owner;
  Scheduler_Node *idle_node;
 
  owner = _Scheduler_Node_get_owner( node );
  _Assert( _Scheduler_Node_get_user( node ) == idle );
  _Scheduler_Node_set_user( node, owner );
  node->idle = NULL;
  idle_node = _Thread_Scheduler_get_home_node( idle );
  ( *release_idle_node )( idle_node, arg );
}
 
static inline Thread_Control *_Scheduler_Release_idle_thread_if_necessary(
  Scheduler_Node             *node,
  Scheduler_Release_idle_node release_idle_node,
  void                        *arg
)
{
  Thread_Control *idle;
 
  idle = _Scheduler_Node_get_idle( node );
 
  if ( idle != NULL ) {
    _Scheduler_Release_idle_thread( node, idle, release_idle_node, arg );
  }
 
  return idle;
}
 
static inline void _Scheduler_Discard_idle_thread(
  Thread_Control             *the_thread,
  Scheduler_Node             *node,
  Scheduler_Release_idle_node release_idle_node,
  void                       *arg
)
{
  Thread_Control  *idle;
  Per_CPU_Control *cpu;
 
  idle = _Scheduler_Node_get_idle( node );
  _Scheduler_Release_idle_thread( node, idle, release_idle_node, arg );
 
  cpu = _Thread_Get_CPU( idle );
  _Thread_Set_CPU( the_thread, cpu );
  _Thread_Dispatch_update_heir( _Per_CPU_Get(), cpu, the_thread );
}
#endif
 
static inline 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 defined(RTEMS_SCORE_THREAD_HAS_SCHEDULER_CHANGE_INHIBITORS)
  if ( the_thread->is_scheduler_change_inhibited ) {
    return STATUS_RESOURCE_IN_USE;
  }
#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 )
#if defined(RTEMS_SMP)
      || !_Chain_Has_only_one_node( &the_thread->Scheduler.Wait_nodes )
      || the_thread->Scheduler.pin_level != 0
#endif
  ) {
    _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)
  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
      ) != STATUS_SUCCESSFUL
  ) {
    _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;
  }
 
  _Assert( the_thread->Scheduler.pinned_scheduler == NULL );
  the_thread->Scheduler.home_scheduler = 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,
      PRIORITY_GROUP_LAST
    );
 
    if ( _States_Is_ready( current_state ) ) {
      _Scheduler_Unblock( the_thread );
    }
 
    return STATUS_SUCCESSFUL;
  }
#endif
 
  _Scheduler_Node_set_priority(
    new_scheduler_node,
    priority,
    PRIORITY_GROUP_LAST
  );
  _Scheduler_Update_priority( the_thread );
  return STATUS_SUCCESSFUL;
}
 
#ifdef __cplusplus
}
#endif
 
#endif
/* end of include file */