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Diffstat (limited to 'nuttx/sched/sched_processtimer.c')
| -rw-r--r-- | nuttx/sched/sched_processtimer.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/nuttx/sched/sched_processtimer.c b/nuttx/sched/sched_processtimer.c new file mode 100644 index 000000000..2224b7691 --- /dev/null +++ b/nuttx/sched/sched_processtimer.c @@ -0,0 +1,190 @@ +/************************************************************************ + * sched/sched_processtimer.c + * + * Copyright (C) 2007, 2009 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 <nuttx/compiler.h> + +#if CONFIG_RR_INTERVAL > 0 +# include <sched.h> +# include <nuttx/arch.h> +#endif + +#include "os_internal.h" +#include "wd_internal.h" +#include "clock_internal.h" + +/************************************************************************ + * Definitions + ************************************************************************/ + +/************************************************************************ + * Private Type Declarations + ************************************************************************/ + +/************************************************************************ + * Global Variables + ************************************************************************/ + +/************************************************************************ + * Private Variables + ************************************************************************/ + +/************************************************************************ + * Private Functions + ************************************************************************/ + +static void sched_process_timeslice(void) +{ +#if CONFIG_RR_INTERVAL > 0 + _TCB *rtcb; + + /* Check if the currently executing task uses round robin + * scheduling. + */ + + rtcb = (_TCB*)g_readytorun.head; + if ((rtcb->flags & TCB_FLAG_ROUND_ROBIN) != 0) + { + /* Yes, check if decrementing the timeslice counter + * would cause the timeslice to expire + */ + + if (rtcb->timeslice <= 1) + { + /* Yes, Now check if the task has pre-emption disabled. + * If so, then we will freeze the timeslice count at + * the value until the next tick after pre-emption + * has been enabled. + */ + + if (!rtcb->lockcount) + { + /* Reset the timeslice in any case. */ + + rtcb->timeslice = CONFIG_RR_INTERVAL / MSEC_PER_TICK; + + /* We know we are at the head of the ready to run + * prioritized list. We must be the highest priority + * task eligible for execution. Check the next task + * in the ready to run list. If it is the same + * priority, then we need to relinquish the CPU and + * give that task a shot. + */ + + if (rtcb->flink && + rtcb->flink->sched_priority >= rtcb->sched_priority) + { + /* Just resetting the task priority to its current + * value. This this will cause the task to be + * rescheduled behind any other tasks at the same + * priority. + */ + + up_reprioritize_rtr(rtcb, rtcb->sched_priority); + } + } + } + else + { + /* Decrement the timeslice counter */ + + rtcb->timeslice--; + } + } +#endif +} + +/************************************************************************ + * Public Functions + ************************************************************************/ + +/************************************************************************ + * System Timer Hooks + * + * These are standard interfaces that are exported by the OS + * for use by the architecture specific logic + * + ************************************************************************/ + +/************************************************************************ + * Name: sched_process_timer + * + * Description: + * This function handles system timer events. + * The timer interrupt logic itself is implemented in the + * architecture specific code, but must call the following OS + * function periodically -- the calling interval must be + * MSEC_PER_TICK + * + * Inputs: + * None + * + * Return Value: + * None + * + ************************************************************************/ + +void sched_process_timer(void) +{ + /* Increment the system time (if in the link) */ + +#ifndef CONFIG_DISABLE_CLOCK +#ifdef CONFIG_HAVE_WEAKFUNCTIONS + if (clock_timer != NULL) +#endif + { + clock_timer(); + } +#endif + + /* Process watchdogs (if in the link) */ + +#ifdef CONFIG_HAVE_WEAKFUNCTIONS + if (wd_timer != NULL) +#endif + { + wd_timer(); + } + + /* Check if the currently executing task has exceeded its + * timeslice. + */ + + sched_process_timeslice(); +} |