| /**************************************************************************** |
| * sched/work_thread.c |
| * |
| * Copyright (C) 2009-2011 Gregory Nutt. All rights reserved. |
| * Author: Gregory Nutt <spudmonkey@racsa.co.cr> |
| * |
| * 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 <queue.h> |
| #include <assert.h> |
| #include <errno.h> |
| #include <debug.h> |
| |
| #include <nuttx/arch.h> |
| #include <nuttx/wqueue.h> |
| #include <nuttx/clock.h> |
| |
| #include "os_internal.h" |
| #include "work_internal.h" |
| |
| #ifdef CONFIG_SCHED_WORKQUEUE |
| |
| /**************************************************************************** |
| * Pre-processor Definitions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Private Type Declarations |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Public Variables |
| ****************************************************************************/ |
| |
| /* The queue of pending work */ |
| |
| struct dq_queue_s g_work; |
| |
| /* The task ID of the worker thread */ |
| |
| #ifdef CONFIG_SCHED_WORKQUEUE |
| pid_t g_worker; |
| #endif |
| |
| /**************************************************************************** |
| * Private Variables |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Private Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| /**************************************************************************** |
| * Name: work_thread |
| * |
| * Description: |
| * This is the main worker thread that performs actions placed on the work |
| * list. It also performs periodic garbage collection (that is performed |
| * by the idle thread if CONFIG_SCHED_WORKQUEUE is not defined). |
| * |
| * Input parameters: |
| * argc, argv (not used) |
| * |
| * Returned Value: |
| * Does not return |
| * |
| ****************************************************************************/ |
| |
| int work_thread(int argc, char *argv[]) |
| { |
| volatile FAR struct work_s *work; |
| worker_t worker; |
| FAR void *arg; |
| uint32_t elapsed; |
| uint32_t remaining; |
| uint32_t next; |
| int usec; |
| irqstate_t flags; |
| |
| /* Loop forever */ |
| |
| usec = CONFIG_SCHED_WORKPERIOD; |
| flags = irqsave(); |
| for (;;) |
| { |
| /* Wait awhile to check the work list. We will wait here until either |
| * the time elapses or until we are awakened by a signal. |
| */ |
| |
| usleep(usec); |
| irqrestore(flags); |
| |
| /* First, 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 lower priority). |
| */ |
| |
| sched_garbagecollection(); |
| |
| /* Then process queued work. We need to keep interrupts disabled while |
| * we process items in the work list. |
| */ |
| |
| next = CONFIG_SCHED_WORKPERIOD / USEC_PER_TICK; |
| flags = irqsave(); |
| work = (FAR struct work_s *)g_work.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. |
| */ |
| |
| elapsed = g_system_timer - work->qtime; |
| if (elapsed >= work->delay) |
| { |
| /* Remove the ready-to-execute work from the list */ |
| |
| (void)dq_rem((struct dq_entry_s *)work, &g_work); |
| |
| /* 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; |
| arg = work->arg; |
| |
| /* Mark the work as no longer being queued */ |
| |
| work->worker = NULL; |
| |
| /* Do the work. Re-enable interrupts while the work is being |
| * performed... we don't have any idea how long that will take! |
| */ |
| |
| irqrestore(flags); |
| worker(arg); |
| |
| /* Now, unfortunately, since we re-enabled interrupts we don't |
| * know the state of the work list and we will have to start |
| * back at the head of the list. |
| */ |
| |
| flags = irqsave(); |
| work = (FAR struct work_s *)g_work.head; |
| } |
| else |
| { |
| /* This one is not ready.. will it be ready before the next |
| * scheduled wakeup interval? |
| */ |
| |
| remaining = elapsed - work->delay; |
| 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; |
| } |
| } |
| |
| /* Now calculate the microsecond delay we should wait */ |
| |
| usec = next * USEC_PER_TICK; |
| } |
| |
| return OK; /* To keep some compilers happy */ |
| } |
| #endif /* CONFIG_SCHED_WORKQUEUE */ |
