px4-firmware/nuttx/sched/sched_removereadytorun.c

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/****************************************************************************
* shced/sched_removereadytorun.c
*
* Copyright (C) 2007-2009, 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 <stdbool.h>
#include <queue.h>
#include <assert.h>
#include "os_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sched_removereadytorun
*
* Description:
* This function removes a TCB from the ready to run list.
*
* Inputs:
* rtcb - Points to the TCB that is ready-to-run
*
* Return Value:
* true if the currently active task (the head of the
* g_readytorun list) has changed.
*
* Assumptions:
* - The caller has established a critical section before calling this
* function (calling sched_lock() first is NOT a good idea -- use irqsave()).
* - The caller handles the condition that occurs if the
* the head of the g_readytorun list is changed.
*
****************************************************************************/
bool sched_removereadytorun(FAR _TCB *rtcb)
{
bool ret = false;
/* Check if the TCB to be removed is at the head of the ready to run list.
* In this case, we are removing the currently active task.
*/
if (!rtcb->blink)
{
/* There must always be at least one task in the list (the idle task) */
ASSERT(rtcb->flink != NULL);
/* Inform the instrumentation layer that we are switching tasks */
sched_note_switch(rtcb, rtcb->flink);
rtcb->flink->task_state = TSTATE_TASK_RUNNING;
ret = true;
}
/* Remove the TCB from the ready-to-run list */
dq_rem((FAR dq_entry_t*)rtcb, (dq_queue_t*)&g_readytorun);
rtcb->task_state = TSTATE_TASK_INVALID;
return ret;
}