nuttx/libs/libc/wqueue/work_usrthread.c

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/****************************************************************************
* libs/libc/wqueue/work_usrthread.c
*
* Copyright (C) 2009-2018 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 <stdint.h>
#include <unistd.h>
#include <pthread.h>
#include <signal.h>
#include <sched.h>
#include <errno.h>
#include <assert.h>
#include <queue.h>
#include <nuttx/semaphore.h>
#include <nuttx/clock.h>
#include <nuttx/wqueue.h>
#include "wqueue/wqueue.h"
#if defined(CONFIG_LIB_USRWORK) && !defined(__KERNEL__)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Use CLOCK_MONOTONIC if it is available. CLOCK_REALTIME can cause bad
* delays if the time is changed.
*/
#ifdef CONFIG_CLOCK_MONOTONIC
# define WORK_CLOCK CLOCK_MONOTONIC
#else
# define WORK_CLOCK CLOCK_REALTIME
#endif
#ifdef CONFIG_SYSTEM_TIME64
# define WORK_DELAY_MAX UINT64_MAX
#else
# define WORK_DELAY_MAX UINT32_MAX
#endif
#ifndef MIN
# define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/* The state of the user mode work queue. */
struct usr_wqueue_s g_usrwork;
/* This semaphore supports exclusive access to the user-mode work queue */
#ifdef CONFIG_BUILD_PROTECTED
sem_t g_usrsem;
#else
pthread_mutex_t g_usrmutex;
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: work_process
*
* Description:
* This is the logic that performs actions placed on any work list. This
* logic is the common underlying logic to all work queues. This logic is
* part of the internal implementation of each work queue; it should not
* be called from application level logic.
*
* Input Parameters:
* wqueue - Describes the work queue to be processed
*
* Returned Value:
* None
*
****************************************************************************/
void work_process(FAR struct usr_wqueue_s *wqueue)
{
volatile FAR struct work_s *work;
sigset_t sigset;
sigset_t oldset;
worker_t worker;
FAR void *arg;
clock_t elapsed;
clock_t remaining;
clock_t stick;
clock_t ctick;
clock_t next;
int ret;
/* Then process queued work. Lock the work queue while we process items
* in the work list.
*/
next = WORK_DELAY_MAX;
ret = work_lock();
if (ret < 0)
{
/* Break out earlier if we were awakened by a signal */
return;
}
/* Set up the signal mask */
sigemptyset(&sigset);
sigaddset(&sigset, SIGWORK);
/* Get the time that we started this polling cycle in clock ticks. */
stick = clock();
/* And check each entry in the work queue. Since we have locked the
* work queue we know: (1) we will not be suspended unless we do
* so ourselves, and (2) there will be no changes to the work queue
*/
work = (FAR struct work_s *)wqueue->q.head;
while (work)
{
/* Is this work ready? It is ready if there is no delay or if
* the delay has elapsed. qtime is the time that the work was added
* to the work queue. It will always be greater than or equal to
* zero. Therefore a delay of zero will always execute immediately.
*/
ctick = clock();
elapsed = ctick - work->qtime;
if (elapsed >= work->delay)
{
/* Remove the ready-to-execute work from the list */
(void)dq_rem((struct dq_entry_s *)work, &wqueue->q);
/* Extract the work description from the entry (in case the work
* instance by the re-used after it has been de-queued).
*/
worker = work->worker;
/* Check for a race condition where the work may be nullified
* before it is removed from the queue.
*/
if (worker != NULL)
{
/* Extract the work argument (before unlocking the work queue) */
arg = work->arg;
/* Mark the work as no longer being queued */
work->worker = NULL;
/* Do the work. Unlock the work queue while the work is being
* performed... we don't have any idea how long this will take!
*/
work_unlock();
worker(arg);
/* Now, unfortunately, since we unlocked the work queue we don't
* know the state of the work list and we will have to start
* back at the head of the list.
*/
ret = work_lock();
if (ret < 0)
{
/* Break out earlier if we were awakened by a signal */
return;
}
work = (FAR struct work_s *)wqueue->q.head;
}
else
{
/* Canceled.. Just move to the next work in the list with
* the work queue still locked.
*/
work = (FAR struct work_s *)work->dq.flink;
}
}
else /* elapsed < work->delay */
{
/* This one is not ready.
*
* NOTE that elapsed is relative to the current time,
* not the time of beginning of this queue processing pass.
* So it may need an adjustment.
*/
elapsed += (ctick - stick);
if (elapsed > work->delay)
{
/* The delay has expired while we are processing */
elapsed = work->delay;
}
/* Will it be ready before the next scheduled wakeup interval? */
remaining = work->delay - elapsed;
if (remaining < next)
{
/* Yes.. Then schedule to wake up when the work is ready */
next = remaining;
}
/* Then try the next in the list. */
work = (FAR struct work_s *)work->dq.flink;
}
}
/* Unlock the work queue before waiting. In order to assure that we do
* not lose the SIGWORK signal before waiting, we block the SIGWORK
* signals before unlocking the work queue. That will cause in SIGWORK
* signals directed to the worker thread to pend.
*/
(void)sigprocmask(SIG_BLOCK, &sigset, &oldset);
work_unlock();
if (next == WORK_DELAY_MAX)
{
/* Wait indefinitely until signaled with SIGWORK */
sigwaitinfo(&sigset, NULL);
}
else
{
struct timespec rqtp;
time_t sec;
/* Wait awhile to check the work list. We will wait here until
* either the time elapses or until we are awakened by a signal.
* Interrupts will be re-enabled while we wait.
*/
sec = next / 1000000;
rqtp.tv_sec = sec;
rqtp.tv_nsec = (next - (sec * 1000000)) * 1000;
sigtimedwait(&sigset, NULL, &rqtp);
}
(void)sigprocmask(SIG_SETMASK, &oldset, NULL);
}
/****************************************************************************
* Name: work_usrthread
*
* Description:
* This is the worker thread that performs the actions placed on the user
* work queue.
*
* This is a user mode work queue. It must be used by applications for
* miscellaneous operations. The user work thread must be started by
* application start-up logic by calling work_usrstart().
*
* Input Parameters:
* argc, argv (not used)
*
* Returned Value:
* Does not return
*
****************************************************************************/
#ifdef CONFIG_BUILD_PROTECTED
static int work_usrthread(int argc, char *argv[])
#else
static pthread_addr_t work_usrthread(pthread_addr_t arg)
#endif
{
/* Loop forever */
for (; ; )
{
/* Then process queued work. We need to keep the work queue locked
* while we process items in the work list.
*/
work_process(&g_usrwork);
}
#ifdef CONFIG_BUILD_PROTECTED
return OK; /* To keep some compilers happy */
#else
return NULL; /* To keep some compilers happy */
#endif
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: work_usrstart
*
* Description:
* Start the user mode work queue.
*
* 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_usrstart(void)
{
/* Initialize work queue data structures */
#ifdef CONFIG_BUILD_PROTECTED
{
/* Set up the work queue lock */
(void)nxsem_init(&g_usrsem, 0, 1);
/* Start a user-mode worker thread for use by applications. */
g_usrwork.pid = task_create("uwork",
CONFIG_LIB_USRWORKPRIORITY,
CONFIG_LIB_USRWORKSTACKSIZE,
(main_t)work_usrthread,
(FAR char * const *)NULL);
DEBUGASSERT(g_usrwork.pid > 0);
if (g_usrwork.pid < 0)
{
int errcode = get_errno();
DEBUGASSERT(errcode > 0);
return -errcode;
}
return g_usrwork.pid;
}
#else
{
pthread_t usrwork;
pthread_attr_t attr;
struct sched_param param;
int ret;
/* Set up the work queue lock */
(void)pthread_mutex_init(&g_usrmutex, NULL);
/* Start a user-mode worker thread for use by applications. */
(void)pthread_attr_init(&attr);
(void)pthread_attr_setstacksize(&attr, CONFIG_LIB_USRWORKSTACKSIZE);
#ifdef CONFIG_SCHED_SPORADIC
/* Get the current sporadic scheduling parameters. Those will not be
* modified.
*/
ret = set_getparam(pid, &param);
if (ret < 0)
{
int erroode = get_errno();
return -errcode;
}
#endif
param.sched_priority = CONFIG_LIB_USRWORKPRIORITY;
(void)pthread_attr_setschedparam(&attr, &param);
ret = pthread_create(&usrwork, &attr, work_usrthread, NULL);
if (ret != 0)
{
return -ret;
}
/* Detach because the return value and completion status will not be
* requested.
*/
(void)pthread_detach(usrwork);
g_usrwork.pid = (pid_t)usrwork;
return g_usrwork.pid;
}
#endif
}
#endif /* CONFIG_LIB_USRWORK && !__KERNEL__*/