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Diffstat (limited to 'nuttx/sched/sched_setparam.c')
-rw-r--r-- | nuttx/sched/sched_setparam.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/nuttx/sched/sched_setparam.c b/nuttx/sched/sched_setparam.c new file mode 100644 index 000000000..6ea4e8f74 --- /dev/null +++ b/nuttx/sched/sched_setparam.c @@ -0,0 +1,156 @@ +/**************************************************************************** + * sched/sched_setparam.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 <sys/types.h> +#include <sched.h> +#include <errno.h> + +#include <nuttx/arch.h> + +#include "os_internal.h" + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Type Declarations + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: sched_setparam + * + * Description: + * This function sets the priority of a specified task. + * + * NOTE: Setting a task's priority to the same value has a similar effect + * to sched_yield() -- The task will be moved to after all other tasks + * with the same priority. + * + * Inputs: + * pid - the task ID of the task to reprioritize. If pid is zero, the + * priority of the calling task is changed. + * param - A structure whose member sched_priority is the integer priority. + * The range of valid priority numbers is from SCHED_PRIORITY_MIN + * through SCHED_PRIORITY_MAX. + * + * Return Value: + * On success, sched_setparam() returns 0 (OK). On error, -1 (ERROR) is + * returned, and errno is set appropriately. + * + * EINVAL The parameter 'param' is invalid or does not make sense for the + * current scheduling policy. + * EPERM The calling task does not have appropriate privileges. + * ESRCH The task whose ID is pid could not be found. + * + * Assumptions: + * + ****************************************************************************/ + +int sched_setparam(pid_t pid, const struct sched_param *param) +{ + FAR _TCB *rtcb; + FAR _TCB *tcb; + int ret; + + /* Verify that the requested priority is in the valid range */ + + if (!param) + { + errno = EINVAL; + return ERROR; + } + + /* Prohibit modifications to the head of the ready-to-run task + * list while adjusting the priority + */ + + sched_lock(); + + /* Check if the task to reprioritize is the calling task */ + + rtcb = (FAR _TCB*)g_readytorun.head; + if (pid == 0 || pid == rtcb->pid) + { + tcb = rtcb; + } + + /* The pid is not the calling task, we will have to search for it */ + + else + { + tcb = sched_gettcb(pid); + if (!tcb) + { + /* No task with this pid was found */ + + errno = ESRCH; + sched_unlock(); + return ERROR; + } + } + + /* Then perform the reprioritization */ + + ret = sched_reprioritize(tcb, param->sched_priority); + sched_unlock(); + return ret; +} |