/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSImplClassicScheduler
*
* @brief This source file contains the implementation of
* rtems_scheduler_remove_processor().
*/
/*
* Copyright (c) 2016 embedded brains GmbH. All rights reserved.
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/rtems/scheduler.h>
#include <rtems/score/schedulerimpl.h>
#include <rtems/config.h>
#if defined(RTEMS_SMP)
typedef struct {
const Scheduler_Control *scheduler;
rtems_status_code status;
} Scheduler_Processor_removal_context;
static bool _Scheduler_Check_processor_not_required(
Thread_Control *the_thread,
void *arg
)
{
Scheduler_Processor_removal_context *iter_context;
Thread_queue_Context queue_context;
ISR_lock_Context state_context;
if ( the_thread->is_idle ) {
return false;
}
iter_context = arg;
_Thread_queue_Context_initialize( &queue_context );
_Thread_Wait_acquire( the_thread, &queue_context );
_Thread_State_acquire_critical( the_thread, &state_context );
if (
_Thread_Scheduler_get_home( the_thread ) == iter_context->scheduler
&& !_Processor_mask_Has_overlap(
&the_thread->Scheduler.Affinity,
_Scheduler_Get_processors( iter_context->scheduler )
)
) {
iter_context->status = RTEMS_RESOURCE_IN_USE;
}
_Thread_State_release_critical( the_thread, &state_context );
_Thread_Wait_release( the_thread, &queue_context );
return iter_context->status != RTEMS_SUCCESSFUL;
}
static bool _Scheduler_Check_no_helping(
Thread_Control *the_thread,
void *arg
)
{
Scheduler_Processor_removal_context *iter_context;
ISR_lock_Context lock_context;
const Chain_Node *node;
const Chain_Node *tail;
if ( the_thread->is_idle ) {
return false;
}
iter_context = arg;
_Thread_State_acquire( the_thread, &lock_context );
node = _Chain_Immutable_first( &the_thread->Scheduler.Scheduler_nodes );
tail = _Chain_Immutable_tail( &the_thread->Scheduler.Scheduler_nodes );
do {
const Scheduler_Node *scheduler_node;
const Scheduler_Control *scheduler;
scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node );
scheduler = _Scheduler_Node_get_scheduler( scheduler_node );
if ( scheduler == iter_context->scheduler ) {
iter_context->status = RTEMS_RESOURCE_IN_USE;
break;
}
node = _Chain_Immutable_next( node );
} while ( node != tail );
_Thread_State_release( the_thread, &lock_context );
return iter_context->status != RTEMS_SUCCESSFUL;
}
#endif
rtems_status_code rtems_scheduler_remove_processor(
rtems_id scheduler_id,
uint32_t cpu_index
)
{
const Scheduler_Control *scheduler;
#if defined(RTEMS_SMP)
Scheduler_Processor_removal_context iter_context;
ISR_lock_Context lock_context;
Scheduler_Context *scheduler_context;
Per_CPU_Control *cpu;
Per_CPU_Control *cpu_self;
#endif
scheduler = _Scheduler_Get_by_id( scheduler_id );
if ( scheduler == NULL ) {
return RTEMS_INVALID_ID;
}
if ( cpu_index >= rtems_configuration_get_maximum_processors() ) {
return RTEMS_INVALID_NUMBER;
}
#if defined(RTEMS_SMP)
iter_context.scheduler = scheduler;
iter_context.status = RTEMS_SUCCESSFUL;
scheduler_context = _Scheduler_Get_context( scheduler );
cpu = _Per_CPU_Get_by_index( cpu_index );
_Objects_Allocator_lock();
if ( cpu->Scheduler.control != scheduler ) {
_Objects_Allocator_unlock();
return RTEMS_INVALID_NUMBER;
}
/*
* This prevents the selection of this scheduler instance by new threads in
* case the processor count changes to zero.
*/
_ISR_lock_ISR_disable( &lock_context );
_Scheduler_Acquire_critical( scheduler, &lock_context );
_Processor_mask_Clear( &scheduler_context->Processors, cpu_index );
_Scheduler_Release_critical( scheduler, &lock_context );
_ISR_lock_ISR_enable( &lock_context );
_Thread_Iterate( _Scheduler_Check_processor_not_required, &iter_context );
if (
_Processor_mask_Is_zero( &scheduler_context->Processors ) &&
iter_context.status == RTEMS_SUCCESSFUL
) {
_Thread_Iterate( _Scheduler_Check_no_helping, &iter_context );
}
_ISR_lock_ISR_disable( &lock_context );
_Scheduler_Acquire_critical( scheduler, &lock_context );
if ( iter_context.status == RTEMS_SUCCESSFUL ) {
Thread_Control *idle;
Scheduler_Node *scheduler_node;
cpu->Scheduler.control = NULL;
cpu->Scheduler.context = NULL;
idle = ( *scheduler->Operations.remove_processor )( scheduler, cpu );
cpu->Scheduler.idle_if_online_and_unused = idle;
scheduler_node = _Thread_Scheduler_get_home_node( idle );
_Priority_Plain_extract(
&scheduler_node->Wait.Priority,
&idle->Real_priority
);
_Assert( _Priority_Is_empty( &scheduler_node->Wait.Priority ) );
_Chain_Extract_unprotected( &scheduler_node->Thread.Wait_node );
_Assert( _Chain_Is_empty( &idle->Scheduler.Wait_nodes ) );
_Chain_Extract_unprotected( &scheduler_node->Thread.Scheduler_node.Chain );
_Assert( _Chain_Is_empty( &idle->Scheduler.Scheduler_nodes ) );
} else {
_Processor_mask_Set( &scheduler_context->Processors, cpu_index );
}
cpu_self = _Thread_Dispatch_disable_critical( &lock_context );
_Scheduler_Release_critical( scheduler, &lock_context );
_ISR_lock_ISR_enable( &lock_context );
_Thread_Dispatch_direct( cpu_self );
_Objects_Allocator_unlock();
return iter_context.status;
#else
return RTEMS_RESOURCE_IN_USE;
#endif
}
