incubator-nuttx/sched/wqueue/kwork_lpthread.c

229 lines
7.3 KiB
C

/****************************************************************************
* sched/wqueue/work_lpthread.c
*
* Copyright (C) 2009-2014 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <unistd.h>
#include <sched.h>
#include <string.h>
#include <errno.h>
#include <queue.h>
#include <debug.h>
#include <nuttx/wqueue.h>
#include <nuttx/kthread.h>
#include <nuttx/kmalloc.h>
#include <nuttx/clock.h>
#include "wqueue/wqueue.h"
#ifdef CONFIG_SCHED_LPWORK
/****************************************************************************
* Public Data
****************************************************************************/
/* The state of the kernel mode, low priority work queue(s). */
struct lp_wqueue_s g_lpwork;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: work_lpthread
*
* Description:
* These are the worker thread(s) that performs the actions placed on the
* low priority work queue.
*
* These, along with the higher priority worker thread are the kernel mode
* work queues (also build in the flat build). One of these threads also
* performs periodic garbage collection (that would otherwise be performed
* by the idle thread if CONFIG_SCHED_WORKQUEUE is not defined). That will
* be the lower priority worker thread if it is available.
*
* All kernel mode worker threads are started by the OS during normal
* bring up. This entry point is referenced by OS internally and should
* not be accessed by application logic.
*
* Input parameters:
* argc, argv (not used)
*
* Returned Value:
* Does not return
*
****************************************************************************/
static int work_lpthread(int argc, char *argv[])
{
#if CONFIG_SCHED_LPNTHREADS > 0
int wndx;
pid_t me = getpid();
int i;
/* Find out thread index by search the workers in g_lpwork */
for (wndx = 0, i = 0; i < CONFIG_SCHED_LPNTHREADS; i++)
{
if (g_lpwork.worker[i].pid == me)
{
wndx = i;
break;
}
}
DEBUGASSERT(i < CONFIG_SCHED_LPNTHREADS);
#endif
/* Loop forever */
for (; ; )
{
#if CONFIG_SCHED_LPNTHREADS > 0
/* Thread 0 is special. Only thread 0 performs period garbage collection */
if (wndx > 0)
{
/* The other threads will perform work, waiting indefinitely until
* signalled for the next work availability.
*
* The special value of zero for the poll period instructs work_process
* to wait indefinitely until a signal is received.
*/
work_process((FAR struct kwork_wqueue_s *)&g_lpwork, 0, wndx);
}
else
#endif
{
/* Perform garbage collection. This cleans-up memory de-allocations
* that were queued because they could not be freed in that execution
* context (for example, if the memory was freed from an interrupt handler).
* NOTE: If the work thread is disabled, this clean-up is performed by
* the IDLE thread (at a very, very low priority).
*
* In the event of multiple low priority threads, on index == 0 will do
* the garbage collection.
*/
sched_garbage_collection();
/* Then process queued work. work_process will not return until:
* (1) there is no further work in the work queue, and (2) the polling
* period provided by g_lpwork.delay expires.
*/
work_process((FAR struct kwork_wqueue_s *)&g_lpwork, g_lpwork.delay, 0);
}
}
return OK; /* To keep some compilers happy */
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: work_lpstart
*
* Description:
* Start the low-priority, kernel-mode worker thread(s)
*
* Input parameters:
* None
*
* Returned Value:
* The task ID of the worker thread is returned on success. A negated
* errno value is returned on failure.
*
****************************************************************************/
int work_lpstart(void)
{
pid_t pid;
int wndx;
/* Initialize work queue data structures */
memset(&g_lpwork, 0, sizeof(struct kwork_wqueue_s));
g_lpwork.delay = CONFIG_SCHED_LPWORKPERIOD / USEC_PER_TICK;
dq_init(&g_lpwork.q);
/* Don't permit any of the threads to run until we have fully initialized
* g_lpwork.
*/
sched_lock();
/* Start the low-priority, kernel mode worker thread(s) */
svdbg("Starting low-priority kernel worker thread(s)\n");
for (wndx = 0; wndx < CONFIG_SCHED_LPNTHREADS; wndx++)
{
pid = kernel_thread(LPWORKNAME, CONFIG_SCHED_LPWORKPRIORITY,
CONFIG_SCHED_LPWORKSTACKSIZE,
(main_t)work_lpthread,
(FAR char * const *)NULL);
DEBUGASSERT(pid > 0);
if (pid < 0)
{
int errcode = errno;
DEBUGASSERT(errcode > 0);
slldbg("kernel_thread %d failed: %d\n", wndx, errcode);
sched_unlock();
return -errcode;
}
g_lpwork.worker[wndx].pid = pid;
g_lpwork.worker[wndx].busy = true;
}
sched_unlock();
return g_lpwork.worker[0].pid;
}
#endif /* CONFIG_SCHED_LPWORK */