98f6034444
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4510 42af7a65-404d-4744-a932-0658087f49c3
130 lines
5.0 KiB
C
130 lines
5.0 KiB
C
/****************************************************************************
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* sched/sched_reprioritize.c
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*
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* Copyright (C) 2009, 2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <sched.h>
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#include <errno.h>
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#include "os_internal.h"
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#ifdef CONFIG_PRIORITY_INHERITANCE
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/****************************************************************************
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* Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Type Declarations
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****************************************************************************/
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/****************************************************************************
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* Global Variables
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****************************************************************************/
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/****************************************************************************
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* Private Variables
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****************************************************************************/
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: sched_reprioritize
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*
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* Description:
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* This function sets the priority of a specified task.
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*
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* NOTE: Setting a task's priority to the same value has a similar
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* effect to sched_yield() -- The task will be moved to after all other
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* tasks with the same priority.
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*
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* Inputs:
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* tcb - the TCB of task to reprioritize.
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* sched_priority - The new task priority
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*
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* Return Value:
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* On success, sched_setparam() returns 0 (OK). On error, -1
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* (ERROR) is returned, and errno is set appropriately.
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*
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* EINVAL The parameter 'param' is invalid or does not make
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* sense for the current scheduling policy.
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* EPERM The calling task does not have appropriate privileges.
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* ESRCH The task whose ID is pid could not be found.
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*
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* Assumptions:
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*
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****************************************************************************/
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int sched_reprioritize(FAR _TCB *tcb, int sched_priority)
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{
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/* This function is equivalent to sched_setpriority() BUT it also has the
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* side effect of discarding all priority inheritance history. This is
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* done only on explicit, user-initiated reprioritization.
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*/
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int ret = sched_setpriority(tcb, sched_priority);
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if (ret == 0)
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{
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/* Reset the base_priority -- the priority that the thread would return
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* to once it posts the semaphore.
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*/
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tcb->base_priority = (uint8_t)sched_priority;
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/* Discard any pending reprioritizations as well */
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# if CONFIG_SEM_NNESTPRIO > 0
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tcb->npend_reprio = 0;
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# endif
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}
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return ret;
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}
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#endif /* CONFIG_PRIORITY_INHERITANCE */
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