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191 lines
6.2 KiB
191 lines
6.2 KiB
/************************************************************************ |
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* sched/sched_processtimer.c |
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* |
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* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr> |
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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 <nuttx/compiler.h> |
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#if CONFIG_RR_INTERVAL > 0 |
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# include <sched.h> |
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# include <nuttx/arch.h> |
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#endif |
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#include "os_internal.h" |
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#include "wd_internal.h" |
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#include "clock_internal.h" |
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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 Functions |
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************************************************************************/ |
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static void sched_process_timeslice(void) |
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{ |
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#if CONFIG_RR_INTERVAL > 0 |
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_TCB *rtcb; |
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/* Check if the currently executing task uses round robin |
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* scheduling. |
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*/ |
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rtcb = (_TCB*)g_readytorun.head; |
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if ((rtcb->flags & TCB_FLAG_ROUND_ROBIN) != 0) |
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{ |
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/* Yes, check if decrementing the timeslice counter |
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* would cause the timeslice to expire |
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*/ |
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if (rtcb->timeslice <= 1) |
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{ |
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/* Yes, Now check if the task has pre-emption disabled. |
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* If so, then we will freeze the timeslice count at |
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* the value until the next tick after pre-emption |
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* has been enabled. |
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*/ |
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if (!rtcb->lockcount) |
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{ |
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/* Reset the timeslice in any case. */ |
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rtcb->timeslice = CONFIG_RR_INTERVAL / MSEC_PER_TICK; |
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/* We know we are at the head of the ready to run |
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* prioritized list. We must be the highest priority |
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* task eligible for execution. Check the next task |
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* in the ready to run list. If it is the same |
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* priority, then we need to relinquish the CPU and |
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* give that task a shot. |
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*/ |
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if (rtcb->flink && |
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rtcb->flink->sched_priority >= rtcb->sched_priority) |
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{ |
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/* Just resetting the task priority to its current |
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* value. This this will cause the task to be |
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* rescheduled behind any other tasks at the same |
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* priority. |
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*/ |
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up_reprioritize_rtr(rtcb, rtcb->sched_priority); |
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} |
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} |
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} |
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else |
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{ |
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/* Decrement the timeslice counter */ |
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rtcb->timeslice--; |
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} |
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} |
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#endif |
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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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* System Timer Hooks |
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* |
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* These are standard interfaces that are exported by the OS |
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* for use by the architecture specific logic |
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* |
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************************************************************************/ |
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/************************************************************************ |
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* Name: sched_process_timer |
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* |
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* Description: |
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* This function handles system timer events. |
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* The timer interrupt logic itself is implemented in the |
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* architecture specific code, but must call the following OS |
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* function periodically -- the calling interval must be |
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* MSEC_PER_TICK |
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* |
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* Inputs: |
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* None |
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* |
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* Return Value: |
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* None |
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* |
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************************************************************************/ |
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void sched_process_timer(void) |
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{ |
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/* Increment the system time (if in the link) */ |
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#ifndef CONFIG_DISABLE_CLOCK |
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#ifdef CONFIG_HAVE_WEAKFUNCTIONS |
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if (clock_timer != NULL) |
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#endif |
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{ |
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clock_timer(); |
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} |
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#endif |
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/* Process watchdogs (if in the link) */ |
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#ifdef CONFIG_HAVE_WEAKFUNCTIONS |
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if (wd_timer != NULL) |
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#endif |
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{ |
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wd_timer(); |
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} |
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/* Check if the currently executing task has exceeded its |
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* timeslice. |
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*/ |
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sched_process_timeslice(); |
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}
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