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Add support for priority inheritance on the low priority worker queue

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This commit is contained in:
Gregory Nutt 2014-10-07 07:41:52 -06:00
parent 03b0dc12c7
commit d7843c8e24
5 changed files with 428 additions and 10 deletions
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44
include/nuttx/wqueue.h
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@ -1,7 +1,7 @@
/****************************************************************************
* include/nuttx/wqueue.h
*
* Copyright (C) 2009, 2011-2013 Gregory Nutt. All rights reserved.
* Copyright (C) 2009, 2011-2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
@ -486,6 +486,48 @@ int work_signal(int qid);
#define work_available(work) ((work)->worker == NULL)
/****************************************************************************
* Name: lpwork_boostpriority
*
* Description:
* Called by the work queue client to assure that the priority of the low-
* priority worker thread is at least at the requested level, reqprio. This
* function would normally be called just before calling work_queue().
*
* Parameters:
* reqprio - Requested minimum worker thread priority
*
* Return Value:
* None
*
****************************************************************************/
#if defined(CONFIG_SCHED_LPWORK) && defined(CONFIG_PRIORITY_INHERITANCE)
void lpwork_boostpriority(uint8_t reqprio);
#endif
/****************************************************************************
* Name: lpwork_restorepriority
*
* Description:
* This function is called to restore the priority after it was previously
* boosted. This is often done by client logic on the worker thread when
* the scheduled work completes. It will check if we need to drop the
* priority of the worker thread.
*
* Parameters:
* reqprio - Previously requested minimum worker thread priority to be
* "unboosted"
*
* Return Value:
* None
*
****************************************************************************/
#if defined(CONFIG_SCHED_LPWORK) && defined(CONFIG_PRIORITY_INHERITANCE)
void lpwork_restorepriority(uint8_t reqprio);
#endif
#undef EXTERN
#ifdef __cplusplus
}

4
libc/Kconfig
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@ -452,9 +452,9 @@ if SCHED_LPWORK
config SCHED_LPWORKPRIORITY
int "Low priority worker thread priority"
default 100
default 50
---help---
The execution priority of the lopwer priority worker thread. Default: 192
The execution priority of the lopwer priority worker thread. Default: 50
config SCHED_LPWORKPERIOD
int "Low priority worker thread period"

11
sched/Makefile
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@ -35,6 +35,9 @@
-include $(TOPDIR)/Make.defs
ASRCS =
CSRCS =
VPATH =
DEPPATH = --dep-path .
@ -53,13 +56,7 @@ include mqueue/Make.defs
include clock/Make.defs
include timer/Make.defs
include environ/Make.defs
ASRCS =
CSRCS = $(INIT_SRCS) $(IRQ_SRCS) $(PG_SRCS) $(GRP_SRCS) $(SCHED_SRCS)
CSRCS += $(TSK_SRCS) $(ERRNO_SRCS) $(WDOG_SRCS) $(SEM_SRCS)
CSRCS += $(SIGNAL_SRCS) $(PTHREAD_SRCS) $(MQUEUE_SRCS) $(CLOCK_SRCS)
CSRCS += $(TIMER_SRCS) $(ENV_SRCS)
include wqueue/Make.defs
AOBJS = $(ASRCS:.S=$(OBJEXT))
COBJS = $(CSRCS:.c=$(OBJEXT))

54
sched/wqueue/Make.defs Normal file
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@ -0,0 +1,54 @@
############################################################################
# sched/wqueue/Make.defs
#
# Copyright (C) 2014 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.
#
############################################################################
# Add work queue files
ifeq ($(CONFIG_SCHED_WORKQUEUE),y)
# Add low priority work queue files
ifeq ($(CONFIG_SCHED_LPWORK),y)
ifeq ($(CONFIG_PRIORITY_INHERITANCE),y)
CSRCS += work_inherit.c
# Include wqueue build support
DEPPATH += --dep-path wqueue
VPATH += :wqueue
endif # CONFIG_PRIORITY_INHERITANCE
endif # CONFIG_SCHED_LPWORK
endif # CONFIG_SCHED_WORKQUEUE

325
sched/wqueue/work_inherit.c Normal file
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@ -0,0 +1,325 @@
/****************************************************************************
* sched/environ/env_putenv.c
*
* Copyright (C) 2007-2009, 2011 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 <sched.h>
#include <nuttx/wqueue.h>
#include "sched/sched.h"
#if defined(CONFIG_SCHED_WORKQUEUE) && defined(CONFIG_SCHED_LPWORK) && \
defined(CONFIG_PRIORITY_INHERITANCE)
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lpwork_boostpriority
*
* Description:
* Called by the work queue client to assure that the priority of the low-
* priority worker thread is at least at the requested level, reqprio. This
* function would normally be called just before calling work_queue().
*
* Parameters:
* reqprio - Requested minimum worker thread priority
*
* Return Value:
* None
*
****************************************************************************/
void lpwork_boostpriority(uint8_t reqprio)
{
FAR struct tcb_s *wtcb;
irqstate_t flags;
pid_t wpid;
/* Get the process ID of the low priority worker thread from the low
* priority work queue. Then get the TCB of the low priority worker
* thread from the process ID.
*/
wpid = g_work[LPWORK].pid;
wtcb = sched_gettcb(wpid);
/* Prevent context switches until we get the priorities right */
flags = irqsave();
sched_lock();
#if CONFIG_SEM_NNESTPRIO > 0
/* If the priority of the client thread that is greater than the base
* priority of the worker thread, then we may need to adjust the worker
* thread's priority now or later to that priority.
*/
if (reqprio > wtcb->base_priority)
{
/* If the new priority is greater than the current, possibly already
* boosted priority of the worker thread, then we will have to raise
* the worker thread's priority now.
*/
if (reqprio > wtcb->sched_priority)
{
/* If the current priority of worker thread has already been
* boosted, then add the boost priority to the list of restoration
* priorities. When the higher priority waiter thread gets its
* count, then we need to revert the worker thread to this saved
* priority (not to its base priority).
*/
if (wtcb->sched_priority > wtcb->base_priority)
{
/* Save the current, boosted priority of the worker thread. */
if (wtcb->npend_reprio < CONFIG_SEM_NNESTPRIO)
{
wtcb->pend_reprios[wtcb->npend_reprio] = wtcb->sched_priority;
wtcb->npend_reprio++;
}
}
/* Raise the priority of the worker. This cannot cause a context
* switch because we have preemption disabled. The worker thread
* may be marked "pending" and the switch may occur during
* sched_unblock() processing.
*/
(void)sched_setpriority(wtcb, reqprio);
}
else
{
/* The new priority is above the base priority of the worker,
* but not as high as its current working priority. Just put it
* in the list of pending restoration priorities so that when the
* higher priority thread gets its count, we can revert to this
* saved priority and not to the base priority.
*/
wtcb->pend_reprios[wtcb->npend_reprio] = reqprio;
wtcb->npend_reprio++;
}
}
#else
/* If the priority of the client thread that is less than of equal to the
* priority of the worker thread, then do nothing because the thread is
* already running at a sufficient priority.
*/
if (reqprio > wtcb->sched_priority)
{
/* Raise the priority of the worker thread. This cannot cause
* context switch because we have preemption disabled. The task
* will be marked "pending" and the switch will occur during
* sched_unlock() processing.
*/
(void)sched_setpriority(wtcb, reqprio);
}
#endif
sched_unlock();
irqrestore(flags);
}
/****************************************************************************
* Name: lpwork_restorepriority
*
* Description:
* This function is called to restore the priority after it was previously
* boosted. This is often done by client logic on the worker thread when
* the scheduled work completes. It will check if we need to drop the
* priority of the worker thread.
*
* Parameters:
* reqprio - Previously requested minimum worker thread priority to be
* "unboosted"
*
* Return Value:
* None
*
****************************************************************************/
void lpwork_restorepriority(uint8_t reqprio)
{
FAR struct tcb_s *wtcb;
irqstate_t flags;
pid_t wpid;
uint8_t wpriority;
int index;
int selected;
/* Get the process ID of the low priority worker thread from the low
* priority work queue. Then get the TCB of the low priority worker
* thread from the process ID.
*/
wpid = g_work[LPWORK].pid;
wtcb = sched_gettcb(wpid);
/* Prevent context switches until we get the priorities right */
flags = irqsave();
sched_lock();
/* Was the priority of the worker thread boosted? If so, then drop its
* priority back to the correct level. What is the correct level?
*/
if (wtcb->sched_priority != wtcb->base_priority)
{
#if CONFIG_SEM_NNESTPRIO > 0
/* Are there other, pending priority levels to revert to? */
if (wtcb->npend_reprio < 1)
{
/* No... the worker thread has only been boosted once.
* npend_reprio should be 0 and the boosted priority should be the
* priority of the client task (reqprio)
*
* That latter assumption may not be true if the client's priority
* was also boosted so that it no longer matches the wtcb's
* sched_priority. Or if CONFIG_SEM_NNESTPRIO is too small (so
* that we do not have a proper record of the reprioritizations).
*/
DEBUGASSERT(/* wtcb->sched_priority == reqprio && */
wtcb->npend_reprio == 0);
/* Reset the worker's priority back to the base priority. */
sched_reprioritize(wtcb, wtcb->base_priority);
}
/* There are multiple pending priority levels. The worker thread's
* "boosted" priority could greater than or equal to "reqprio" (it could
* be greater if its priority we boosted because it also holds some
* semaphore).
*/
else if (wtcb->sched_priority <= reqprio)
{
/* The worker thread has been boosted to the same priority as the
* waiter thread that just received the count. We will simply
* reprioritize to the next highest pending priority.
*/
/* Find the highest pending priority and remove it from the list */
for (index = 1, selected = 0; index < wtcb->npend_reprio; index++)
{
if (wtcb->pend_reprios[index] > wtcb->pend_reprios[selected])
{
selected = index;
}
}
/* Remove the highest priority pending priority from the list */
wpriority = wtcb->pend_reprios[selected];
index = wtcb->npend_reprio - 1;
if (index > 0)
{
wtcb->pend_reprios[selected] = wtcb->pend_reprios[index];
}
wtcb->npend_reprio = index;
/* And apply that priority to the thread (while retaining the
* base_priority)
*/
sched_setpriority(wtcb, wpriority);
}
else
{
/* The worker thread has been boosted to a higher priority than the
* waiter task. The pending priority should be in the list (unless
* it was lost because of of list overflow or because the worker
* was reprioritized again unbeknownst to the priority inheritance
* logic).
*
* Search the list for the matching priority.
*/
for (index = 0; index < wtcb->npend_reprio; index++)
{
/* Does this pending priority match the priority of the thread
* that just received the count?
*/
if (wtcb->pend_reprios[index] == reqprio)
{
/* Yes, remove it from the list */
selected = wtcb->npend_reprio - 1;
if (selected > 0)
{
wtcb->pend_reprios[index] = wtcb->pend_reprios[selected];
}
wtcb->npend_reprio = selected;
break;
}
}
}
#else
/* There is no alternative restore priorities, drop the priority
* of the worker thread all the way back to the threads "base"
* priority.
*/
sched_reprioritize(wtcb, wtcb->base_priority);
#endif
}
sched_unlock();
irqrestore(flags);
}
#endif /* CONFIG_SCHED_WORKQUEUE && CONFIG_SCHED_LPWORK && CONFIG_PRIORITY_INHERITANCE */