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155 lines
5.3 KiB
155 lines
5.3 KiB
/************************************************************************ |
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* sched/sched_rrgetinterval.c |
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* |
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* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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************************************************************************/ |
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/************************************************************************ |
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* Included Files |
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************************************************************************/ |
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#include <nuttx/config.h> |
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#include <sys/types.h> |
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#include <sched.h> |
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#include <errno.h> |
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#include <nuttx/arch.h> |
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#include "os_internal.h" |
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#include "clock_internal.h" |
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/************************************************************************ |
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* Definitions |
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************************************************************************/ |
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/************************************************************************ |
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* Private Type Declarations |
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************************************************************************/ |
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/************************************************************************ |
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* Global Variables |
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************************************************************************/ |
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/************************************************************************ |
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* Private Variables |
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************************************************************************/ |
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/************************************************************************ |
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* Private Function Prototypes |
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************************************************************************/ |
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/************************************************************************ |
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* Private Functions |
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************************************************************************/ |
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/************************************************************************ |
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* Public Functions |
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************************************************************************/ |
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/************************************************************************ |
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* Name: sched_rr_get_interval |
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* |
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* Description: |
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* sched_rr_get_interval() writes the timeslice interval |
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* for task identified by 'pid' into the timespec structure |
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* pointed to by 'interval.' If pid is zero, the timeslice |
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* for the calling process is written into 'interval. The |
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* identified process should be running under the SCHED_RR |
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* scheduling policy.' |
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* |
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* Inputs: |
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* pid - the task ID of the task. If pid is zero, the |
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* priority of the calling task is returned. |
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* interval - a structure used to return the time slice |
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* |
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* Return Value: |
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* On success, sched_rr_get_interval() returns OK (0). On |
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* error, ERROR (-1) is returned, and errno is set to: |
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* |
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* EFAULT -- Cannot copy to interval |
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* EINVAL Invalid pid. |
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* ENOSYS The system call is not yet implemented. |
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* ESRCH The process whose ID is pid could not be found. |
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* |
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* Assumptions: |
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* |
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************************************************************************/ |
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int sched_rr_get_interval(pid_t pid, struct timespec *interval) |
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{ |
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#if CONFIG_RR_INTERVAL > 0 |
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FAR _TCB *rrtcb; |
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/* If pid is zero, the timeslice for the calling process is |
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* written into 'interval.' |
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*/ |
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if (!pid) |
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{ |
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rrtcb = (FAR _TCB*)g_readytorun.head; |
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} |
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/* Return a special error code on invalid PID */ |
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else if (pid < 0) |
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{ |
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*get_errno_ptr() = EINVAL; |
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return ERROR; |
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} |
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/* Otherwise, lookup the TCB associated with this pid */ |
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else |
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{ |
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rrtcb = sched_gettcb(pid); |
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if (!rrtcb) |
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{ |
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*get_errno_ptr() = ESRCH; |
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return ERROR; |
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} |
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} |
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if (!interval) |
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{ |
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*get_errno_ptr() = EFAULT; |
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return ERROR; |
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} |
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/* Convert the timeslice value from ticks to timespec */ |
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interval->tv_sec = CONFIG_RR_INTERVAL / MSEC_PER_SEC; |
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interval->tv_nsec = (CONFIG_RR_INTERVAL % MSEC_PER_SEC) * NSEC_PER_MSEC; |
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return OK; |
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#else |
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*get_errno_ptr() = ENOSYS; |
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return ERROR; |
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#endif |
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}
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