92 lines
3.0 KiB
C
92 lines
3.0 KiB
C
/****************************************************************************
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* sched/sched/sched_reprioritizertr.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <stdint.h>
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#include <sched.h>
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#include <errno.h>
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#include <nuttx/sched.h>
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#include "sched/sched.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxsched_reprioritize_rtr
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*
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* Description:
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* This function called when the priority of a running or
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* ready-to-run task changes.
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*
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* Input Parameters:
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* tcb - the TCB of task to reprioritize.
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* priority - The new task priority
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*
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* Returned Value:
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* true if the head of the ready-to-run task list has changed indicating
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* a context switch is needed.
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*
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****************************************************************************/
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bool nxsched_reprioritize_rtr(FAR struct tcb_s *tcb, int priority)
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{
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bool switch_needed;
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/* Remove the tcb task from the ready-to-run list.
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* nxsched_remove_readytorun will return true if we just
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* remove the head of the ready to run list.
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*/
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switch_needed = nxsched_remove_readytorun(tcb, false);
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/* Setup up the new task priority */
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tcb->sched_priority = (uint8_t)priority;
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/* Return the task to the specified blocked task list.
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* nxsched_add_readytorun will return true if the task was
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* added to the new list. We will need to perform a context
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* switch only if the EXCLUSIVE or of the two calls is non-zero
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* (i.e., one and only one the calls changes the head of the
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* ready-to-run list).
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*/
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switch_needed ^= nxsched_add_readytorun(tcb);
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/* If we are going to do a context switch, then now is the right
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* time to add any pending tasks back into the ready-to-run list.
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*/
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if (switch_needed && g_pendingtasks.head)
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{
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nxsched_merge_pending();
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}
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return switch_needed;
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}
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