277 lines
8.3 KiB
C
277 lines
8.3 KiB
C
/****************************************************************************
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* sched/wqueue/kwork_inherit.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 <sched.h>
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#include <assert.h>
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#include <debug.h>
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#include <nuttx/irq.h>
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#include <nuttx/wqueue.h>
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#include "sched/sched.h"
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#include "wqueue/wqueue.h"
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#if defined(CONFIG_SCHED_WORKQUEUE) && defined(CONFIG_SCHED_LPWORK) && \
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defined(CONFIG_PRIORITY_INHERITANCE)
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: lpwork_boostworker
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*
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* Description:
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* Called by the work queue client to assure that the priority of the low-
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* priority worker thread is at least at the requested level, reqprio. This
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* function would normally be called just before calling work_queue().
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*
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* Input Parameters:
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* reqprio - Requested minimum worker thread priority
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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static void lpwork_boostworker(pid_t wpid, uint8_t reqprio)
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{
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FAR struct tcb_s *wtcb;
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/* Get the TCB of the low priority worker thread from the process ID. */
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wtcb = nxsched_get_tcb(wpid);
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DEBUGASSERT(wtcb);
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/* REVISIT: Priority multi-boost is not supported */
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DEBUGASSERT(wtcb->boost_priority == 0);
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/* If the priority of the client thread that is greater than the base
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* priority of the worker thread, then we may need to adjust the worker
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* thread's priority now or later to that priority.
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*/
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if (reqprio > wtcb->base_priority)
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{
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/* Save boost priority value as it might be needed in case of multiple
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* re-prioritisations happen, then the priority of the thread can't go
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* below the boost priority value until priority boost is canceled.
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*/
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wtcb->boost_priority = reqprio;
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/* If the priority of the client thread that is less than of equal to
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* the priority of the worker thread, then do nothing because the
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* thread is already running at a sufficient priority.
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*/
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if (reqprio > wtcb->sched_priority)
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{
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/* Raise the priority of the worker thread. This cannot cause
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* context switch because we have preemption disabled. The task
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* will be marked "pending" and the switch will occur during
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* sched_unlock() processing.
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*/
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nxsched_set_priority(wtcb, reqprio);
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}
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}
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}
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/****************************************************************************
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* Name: lpwork_restoreworker
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*
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* Description:
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* This function is called to restore the priority after it was previously
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* boosted. This is often done by client logic on the worker thread when
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* the scheduled work completes. It will check if we need to drop the
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* priority of the worker thread.
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*
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* Input Parameters:
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* reqprio - Previously requested minimum worker thread priority to be
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* "unboosted"
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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static void lpwork_restoreworker(pid_t wpid, uint8_t reqprio)
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{
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FAR struct tcb_s *wtcb;
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/* Get the TCB of the low priority worker thread from the process ID. */
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wtcb = nxsched_get_tcb(wpid);
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DEBUGASSERT(wtcb);
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/* REVISIT: Priority multi-boost is not supported. */
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DEBUGASSERT(wtcb->boost_priority == reqprio);
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/* Clear the threat boost priority. */
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wtcb->boost_priority = 0;
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/* Was the priority of the worker thread boosted? If so, then drop its
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* priority back to the correct level. What is the correct level?
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*/
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if (wtcb->sched_priority != wtcb->base_priority)
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{
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FAR struct semholder_s *pholder;
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uint8_t wpriority;
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/* We attempt to restore task priority to its base priority. If there
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* is any task with the higher priority waiting for the semaphore
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* held by wtcb then this value will be overwritten.
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*/
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wpriority = wtcb->base_priority;
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/* Try to find the highest priority across all the tasks that are
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* waiting for any semaphore held by wtcb.
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*/
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for (pholder = wtcb->holdsem; pholder != NULL;
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pholder = pholder->tlink)
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{
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FAR struct tcb_s *stcb;
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stcb = (FAR struct tcb_s *)dq_peek(SEM_WAITLIST(pholder->sem));
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if (stcb != NULL && stcb->sched_priority > wpriority)
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{
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wpriority = stcb->sched_priority;
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}
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}
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/* Apply the selected priority to the worker thread (hopefully back
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* to the threads base_priority).
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*/
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nxsched_set_priority(wtcb, wpriority);
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}
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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: lpwork_boostpriority
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*
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* Description:
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* Called by the work queue client to assure that the priority of the low-
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* priority worker thread is at least at the requested level, reqprio. This
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* function would normally be called just before calling work_queue().
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*
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* Input Parameters:
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* reqprio - Requested minimum worker thread priority
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void lpwork_boostpriority(uint8_t reqprio)
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{
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irqstate_t flags;
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int wndx;
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/* Clip to the configured maximum priority */
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if (reqprio > CONFIG_SCHED_LPWORKPRIOMAX)
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{
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reqprio = CONFIG_SCHED_LPWORKPRIOMAX;
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}
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/* Prevent context switches until we get the priorities right */
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flags = enter_critical_section();
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sched_lock();
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/* Adjust the priority of every worker thread */
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for (wndx = 0; wndx < CONFIG_SCHED_LPNTHREADS; wndx++)
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{
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lpwork_boostworker(g_lpwork.worker[wndx].pid, reqprio);
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}
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sched_unlock();
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leave_critical_section(flags);
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}
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/****************************************************************************
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* Name: lpwork_restorepriority
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*
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* Description:
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* This function is called to restore the priority after it was previously
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* boosted. This is often done by client logic on the worker thread when
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* the scheduled work completes. It will check if we need to drop the
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* priority of the worker thread.
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*
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* Input Parameters:
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* reqprio - Previously requested minimum worker thread priority to be
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* "unboosted"
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*
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* Returned Value:
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* None
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*
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****************************************************************************/
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void lpwork_restorepriority(uint8_t reqprio)
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{
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irqstate_t flags;
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int wndx;
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/* Clip to the configured maximum priority */
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if (reqprio > CONFIG_SCHED_LPWORKPRIOMAX)
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{
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reqprio = CONFIG_SCHED_LPWORKPRIOMAX;
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}
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/* Prevent context switches until we get the priorities right */
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flags = enter_critical_section();
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sched_lock();
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/* Adjust the priority of every worker thread */
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for (wndx = 0; wndx < CONFIG_SCHED_LPNTHREADS; wndx++)
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{
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lpwork_restoreworker(g_lpwork.worker[wndx].pid, reqprio);
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}
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sched_unlock();
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leave_critical_section(flags);
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}
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#endif /* CONFIG_SCHED_WORKQUEUE && CONFIG_SCHED_LPWORK && \
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* CONFIG_PRIORITY_INHERITANCE */
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