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Diffstat (limited to 'nuttx/sched/sched_setscheduler.c')
-rw-r--r-- | nuttx/sched/sched_setscheduler.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/nuttx/sched/sched_setscheduler.c b/nuttx/sched/sched_setscheduler.c new file mode 100644 index 000000000..7f7f345b4 --- /dev/null +++ b/nuttx/sched/sched_setscheduler.c @@ -0,0 +1,187 @@ +/**************************************************************************** + * sched/sched_setscheduler.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 <sys/types.h> +#include <unistd.h> +#include <sched.h> +#include <errno.h> + +#include <nuttx/arch.h> + +#include "os_internal.h" +#include "clock_internal.h" + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Type Declarations + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name:sched_setscheduler + * + * Description: + * sched_setscheduler() sets both the scheduling policy and the priority + * for the task identified by pid. If pid equals zero, the scheduler of + * the calling task will be set. The parameter 'param' holds the priority + * of the thread under the new policy. + * + * Inputs: + * pid - the task ID of the task to modify. If pid is zero, the calling + * task is modified. + * policy - Scheduling policy requested (either SCHED_FIFO or SCHED_RR) + * param - A structure whose member sched_priority is the new priority. + * The range of valid priority numbers is from SCHED_PRIORITY_MIN + * through SCHED_PRIORITY_MAX. + * + * Return Value: + * On success, sched_setscheduler() returns OK (zero). On error, ERROR + * (-1) is returned, and errno is set appropriately: + * + * EINVAL The scheduling policy is not one of the recognized policies. + * ESRCH The task whose ID is pid could not be found. + * + * Assumptions: + * + ****************************************************************************/ + +int sched_setscheduler(pid_t pid, int policy, + const struct sched_param *param) +{ + FAR _TCB *tcb; +#if CONFIG_RR_INTERVAL > 0 + irqstate_t saved_state; +#endif + int ret; + + /* Check for supported scheduling policy */ + +#if CONFIG_RR_INTERVAL > 0 + if (policy != SCHED_FIFO && policy != SCHED_RR) +#else + if (policy != SCHED_FIFO) +#endif + { + errno = EINVAL; + return ERROR; + } + + /* Check if the task to modify the calling task */ + + if (pid == 0 ) + { + pid = getpid(); + } + + /* Verify that the pid corresponds to a real task */ + + tcb = sched_gettcb(pid); + if (!tcb) + { + errno = ESRCH; + return ERROR; + } + + /* Prohibit any context switches while we muck with priority and scheduler + * settings. + */ + + sched_lock(); + +#if CONFIG_RR_INTERVAL > 0 + /* Further, disable timer interrupts while we set up scheduling policy. */ + + saved_state = irqsave(); + if (policy == SCHED_RR) + { + /* Set round robin scheduling */ + + tcb->flags |= TCB_FLAG_ROUND_ROBIN; + tcb->timeslice = CONFIG_RR_INTERVAL / MSEC_PER_TICK; + } + else + { + /* Set FIFO scheduling */ + + tcb->flags &= ~TCB_FLAG_ROUND_ROBIN; + tcb->timeslice = 0; + } + + irqrestore(saved_state); +#endif + + /* Set the new priority */ + + ret = sched_reprioritize(tcb, param->sched_priority); + sched_unlock(); + + if (ret != OK) + { + return ERROR; + } + else + { + return OK; + } +} + |