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/****************************************************************************
* sched/sched_reprioritize.c
*
* Copyright (C) 2009, 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <sched.h>
#include <errno.h>
#include "os_internal.h"
#ifdef CONFIG_PRIORITY_INHERITANCE
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sched_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.
*
* Inputs:
* tcb - the TCB of task to reprioritize.
* sched_priority - The new task priority
*
* Return Value:
* On success, sched_setparam() returns 0 (OK). On error, -1
* (ERROR) is returned, and errno is set appropriately.
*
* 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.
*
* Assumptions:
*
****************************************************************************/
int sched_reprioritize(FAR struct tcb_s *tcb, int sched_priority)
{
/* This function is equivalent to sched_setpriority() BUT it also has the
* side effect of discarding all priority inheritance history. This is
* done only on explicit, user-initiated reprioritization.
*/
int ret = sched_setpriority(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 */
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