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Diffstat (limited to 'nuttx/sched/sched_rrgetinterval.c')
-rw-r--r-- | nuttx/sched/sched_rrgetinterval.c | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/nuttx/sched/sched_rrgetinterval.c b/nuttx/sched/sched_rrgetinterval.c new file mode 100644 index 0000000000..8dfe99ff35 --- /dev/null +++ b/nuttx/sched/sched_rrgetinterval.c @@ -0,0 +1,156 @@ +/************************************************************ + * sched_rrgetinterval.c + * + * Copyright (C) 2007 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * 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 Gregory Nutt 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 <nuttx/os_external.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_RR + * scheduling 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 + _TCB *rrtcb; + + /* If pid is zero, the timeslice for the calling process is + * written into 'interval.' + */ + + if (!pid) + { + rrtcb = (_TCB*)g_readytorun.head; + } + + /* Return a special error code on invalid PID */ + + else if (pid < 0) + { + *get_errno_ptr() = EINVAL; + return ERROR; + } + + /* Otherwise, lookup the TCB associated with this pid */ + + else + { + rrtcb = sched_gettcb(pid); + if (!rrtcb) + { + *get_errno_ptr() = ESRCH; + return ERROR; + } + } + + if (!interval) + { + *get_errno_ptr() = 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 + *get_errnor_ptr() = ENOSYS; + return ERROR; +#endif +} |