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Diffstat (limited to 'nuttx/sched/sched_rrgetinterval.c')
-rw-r--r-- | nuttx/sched/sched_rrgetinterval.c | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/nuttx/sched/sched_rrgetinterval.c b/nuttx/sched/sched_rrgetinterval.c new file mode 100644 index 000000000..961c58ec5 --- /dev/null +++ b/nuttx/sched/sched_rrgetinterval.c @@ -0,0 +1,157 @@ +/************************************************************************ + * sched/sched_rrgetinterval.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" +#include "clock_internal.h" + +/************************************************************************ + * Definitions + ************************************************************************/ + +/************************************************************************ + * Private Type Declarations + ************************************************************************/ + +/************************************************************************ + * Global Variables + ************************************************************************/ + +/************************************************************************ + * Private Variables + ************************************************************************/ + +/************************************************************************ + * Private Function Prototypes + ************************************************************************/ + +/************************************************************************ + * Private Functions + ************************************************************************/ + +/************************************************************************ + * Public Functions + ************************************************************************/ + +/************************************************************************ + * Name: sched_rr_get_interval + * + * Description: + * sched_rr_get_interval() writes the timeslice interval for task + * identified by 'pid' into the timespec structure pointed to by + * 'interval.' If pid is zero, the timeslice for the calling process + * is written into 'interval. The identified process should be running + * under the SCHED_RRscheduling policy.' + * + * Inputs: + * pid - the task ID of the task. If pid is zero, the priority of the + * calling task is returned. + * interval - a structure used to return the time slice + * + * Return Value: + * On success, sched_rr_get_interval() returns OK (0). On error, + * ERROR (-1) is returned, and errno is set to: + * + * EFAULT -- Cannot copy to interval + * EINVAL Invalid pid. + * ENOSYS The system call is not yet implemented. + * ESRCH The process whose ID is pid could not be found. + * + * Assumptions: + * + ************************************************************************/ + +int sched_rr_get_interval(pid_t pid, struct timespec *interval) +{ +#if CONFIG_RR_INTERVAL > 0 + FAR _TCB *rrtcb; + + /* If pid is zero, the timeslice for the calling process is written + * into 'interval.' + */ + + if (!pid) + { + rrtcb = (FAR _TCB*)g_readytorun.head; + } + + /* Return a special error code on invalid PID */ + + else if (pid < 0) + { + set_errno(EINVAL); + return ERROR; + } + + /* Otherwise, lookup the TCB associated with this pid */ + + else + { + rrtcb = sched_gettcb(pid); + if (!rrtcb) + { + set_errno(ESRCH); + return ERROR; + } + } + + if (!interval) + { + set_errno(EFAULT); + return ERROR; + } + + /* Convert the timeslice value from ticks to timespec */ + + interval->tv_sec = CONFIG_RR_INTERVAL / MSEC_PER_SEC; + interval->tv_nsec = (CONFIG_RR_INTERVAL % MSEC_PER_SEC) * NSEC_PER_MSEC; + + return OK; +#else + set_errno(ENOSYS); + return ERROR; +#endif +} |