nuttx/sched/sched/sched_reprioritize.c

92 lines
3.1 KiB
C

/****************************************************************************
* sched/sched/sched_reprioritize.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 <stdint.h>
#include <sched.h>
#include <errno.h>
#include <nuttx/sched.h>
#include "sched/sched.h"
#ifdef CONFIG_PRIORITY_INHERITANCE
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxsched_reprioritize
*
* Description:
* This function sets the priority of a specified task.
*
* NOTE: Setting a task's priority to the same value has a similar effect
* to sched_yield() -- The task will be moved to after all other tasks
* with the same priority.
*
* Input Parameters:
* tcb - the TCB of task to reprioritize.
* sched_priority - The new task priority
*
* Returned Value:
* On success, sched_reporioritize() returns 0 (OK). On error, a negated
* errno value is returned.
*
* EINVAL The parameter 'param' is invalid or does not make sense for the
* current scheduling policy.
* EPERM The calling task does not have appropriate privileges.
* ESRCH The task whose ID is pid could not be found.
*
****************************************************************************/
int nxsched_reprioritize(FAR struct tcb_s *tcb, int sched_priority)
{
/* This function is equivalent to nxsched_set_priority() BUT it also has
* the side effect of discarding all priority inheritance history. This
* is done only on explicit, user-initiated reprioritization.
*/
int ret = nxsched_set_priority(tcb, sched_priority);
if (ret == 0)
{
/* Reset the base_priority -- the priority that the thread would return
* to once it posts the semaphore.
*/
tcb->base_priority = (uint8_t)sched_priority;
/* Discard any pending reprioritizations as well */
#if CONFIG_SEM_NNESTPRIO > 0
tcb->npend_reprio = 0;
#endif
}
return ret;
}
#endif /* CONFIG_PRIORITY_INHERITANCE */