8935ac4cc3
Gregory Nutt has submitted the SGA and we can mograte the licenses to Apache. Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
/****************************************************************************
|
|
* sched/sched/sched_cpuselect.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <sys/types.h>
|
|
#include <assert.h>
|
|
|
|
#include <nuttx/sched.h>
|
|
|
|
#include "sched/sched.h"
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
#define IMPOSSIBLE_CPU 0xff
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: nxsched_select_cpu
|
|
*
|
|
* Description:
|
|
* Return the index to the CPU with the lowest priority running task,
|
|
* possibly its IDLE task.
|
|
*
|
|
* Input Parameters:
|
|
* affinity - The set of CPUs on which the thread is permitted to run.
|
|
*
|
|
* Returned Value:
|
|
* Index of the CPU with the lowest priority running task
|
|
*
|
|
* Assumptions:
|
|
* Called from within a critical section.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int nxsched_select_cpu(cpu_set_t affinity)
|
|
{
|
|
uint8_t minprio;
|
|
int cpu;
|
|
int i;
|
|
|
|
/* Otherwise, find the CPU that is executing the lowest priority task
|
|
* (possibly its IDLE task).
|
|
*/
|
|
|
|
minprio = SCHED_PRIORITY_MAX;
|
|
cpu = IMPOSSIBLE_CPU;
|
|
|
|
for (i = 0; i < CONFIG_SMP_NCPUS; i++)
|
|
{
|
|
/* If the thread permitted to run on this CPU? */
|
|
|
|
if ((affinity & (1 << i)) != 0)
|
|
{
|
|
FAR struct tcb_s *rtcb = (FAR struct tcb_s *)
|
|
g_assignedtasks[i].head;
|
|
|
|
/* If this thread is executing its IDLE task, the use it. The
|
|
* IDLE task is always the last task in the assigned task list.
|
|
*/
|
|
|
|
if (rtcb->flink == NULL)
|
|
{
|
|
/* The IDLE task should always be assigned to this CPU and have
|
|
* a priority of zero.
|
|
*/
|
|
|
|
DEBUGASSERT(rtcb->sched_priority == 0);
|
|
return i;
|
|
}
|
|
else if (rtcb->sched_priority < minprio)
|
|
{
|
|
DEBUGASSERT(rtcb->sched_priority > 0);
|
|
minprio = rtcb->sched_priority;
|
|
cpu = i;
|
|
}
|
|
}
|
|
}
|
|
|
|
DEBUGASSERT(cpu != IMPOSSIBLE_CPU);
|
|
return cpu;
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|