forked from Archive/PX4-Autopilot
150 lines
5.5 KiB
C
150 lines
5.5 KiB
C
/****************************************************************************
|
|
* sched/sched_addreadytorun.c
|
|
*
|
|
* Copyright (C) 2007-2009 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
|
|
*
|
|
* 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_addreadytorun
|
|
*
|
|
* Description:
|
|
* This function adds a TCB to the ready to run
|
|
* list. If the currently active task has preemption disabled
|
|
* and the new TCB would cause this task to be preempted, the
|
|
* new task is added to the g_pendingtasks list instead. The
|
|
* pending tasks will be made ready-to-run when preemption
|
|
* is unlocked.
|
|
*
|
|
* Inputs:
|
|
* btcb - Points to the blocked 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 has already removed the input rtcb from
|
|
* whatever list it was in.
|
|
* - The caller handles the condition that occurs if the
|
|
* the head of the g_readytorun list is changed.
|
|
*
|
|
****************************************************************************/
|
|
|
|
bool sched_addreadytorun(FAR _TCB *btcb)
|
|
{
|
|
FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head;
|
|
bool ret;
|
|
|
|
/* Check if pre-emption is disabled for the current running
|
|
* task and if the new ready-to-run task would cause the
|
|
* current running task to be preempted.
|
|
*/
|
|
|
|
if (rtcb->lockcount && rtcb->sched_priority < btcb->sched_priority)
|
|
{
|
|
/* Yes. Preemption would occur! Add the new ready-to-run
|
|
* task to the g_pendingtasks task list for now.
|
|
*/
|
|
|
|
sched_addprioritized(btcb, (FAR dq_queue_t*)&g_pendingtasks);
|
|
btcb->task_state = TSTATE_TASK_PENDING;
|
|
ret = false;
|
|
}
|
|
|
|
/* Otherwise, add the new task to the g_readytorun task list */
|
|
|
|
else if (sched_addprioritized(btcb, (FAR dq_queue_t*)&g_readytorun))
|
|
{
|
|
/* Information the instrumentation logic that we are switching tasks */
|
|
|
|
sched_note_switch(rtcb, btcb);
|
|
|
|
/* The new btcb was added at the head of the g_readytorun list. It
|
|
* is now to new active task!
|
|
*/
|
|
|
|
ASSERT(!rtcb->lockcount && btcb->flink != NULL);
|
|
|
|
btcb->task_state = TSTATE_TASK_RUNNING;
|
|
btcb->flink->task_state = TSTATE_TASK_READYTORUN;
|
|
ret = true;
|
|
}
|
|
else
|
|
{
|
|
/* The new btcb was added in the middle of the g_readytorun list */
|
|
|
|
btcb->task_state = TSTATE_TASK_READYTORUN;
|
|
ret = false;
|
|
}
|
|
|
|
return ret;
|
|
}
|