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215 lines
7.3 KiB
215 lines
7.3 KiB
/**************************************************************************** |
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* sched/work_thread.c |
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* |
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* Copyright (C) 2009-2011 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <gnutt@nuttx.org> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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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 <stdint.h> |
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#include <unistd.h> |
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#include <queue.h> |
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#include <assert.h> |
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#include <errno.h> |
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#include <debug.h> |
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#include <nuttx/arch.h> |
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#include <nuttx/wqueue.h> |
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#include <nuttx/clock.h> |
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#include "os_internal.h" |
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#include "work_internal.h" |
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#ifdef CONFIG_SCHED_WORKQUEUE |
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/**************************************************************************** |
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* Pre-processor Definitions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Type Declarations |
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****************************************************************************/ |
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/**************************************************************************** |
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* Public Variables |
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****************************************************************************/ |
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/* The queue of pending work */ |
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struct dq_queue_s g_work; |
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/* The task ID of the worker thread */ |
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#ifdef CONFIG_SCHED_WORKQUEUE |
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pid_t g_worker; |
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#endif |
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/**************************************************************************** |
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* Private Variables |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Functions |
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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: work_thread |
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* |
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* Description: |
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* This is the main worker thread that performs actions placed on the work |
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* list. It also performs periodic garbage collection (that is performed |
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* by the idle thread if CONFIG_SCHED_WORKQUEUE is not defined). |
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* |
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* Input parameters: |
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* argc, argv (not used) |
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* |
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* Returned Value: |
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* Does not return |
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* |
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****************************************************************************/ |
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int work_thread(int argc, char *argv[]) |
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{ |
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volatile FAR struct work_s *work; |
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worker_t worker; |
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FAR void *arg; |
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uint32_t elapsed; |
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uint32_t remaining; |
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uint32_t next; |
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int usec; |
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irqstate_t flags; |
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/* Loop forever */ |
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usec = CONFIG_SCHED_WORKPERIOD; |
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flags = irqsave(); |
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for (;;) |
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{ |
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/* Wait awhile to check the work list. We will wait here until either |
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* the time elapses or until we are awakened by a signal. |
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*/ |
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usleep(usec); |
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irqrestore(flags); |
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/* First, perform garbage collection. This cleans-up memory de-allocations |
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* that were queued because they could not be freed in that execution |
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* context (for example, if the memory was freed from an interrupt handler). |
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* NOTE: If the work thread is disabled, this clean-up is performed by |
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* the IDLE thread (at a very, very lower priority). |
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*/ |
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sched_garbagecollection(); |
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/* Then process queued work. We need to keep interrupts disabled while |
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* we process items in the work list. |
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*/ |
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next = CONFIG_SCHED_WORKPERIOD / USEC_PER_TICK; |
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flags = irqsave(); |
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work = (FAR struct work_s *)g_work.head; |
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while (work) |
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{ |
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/* Is this work ready? It is ready if there is no delay or if |
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* the delay has elapsed. qtime is the time that the work was added |
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* to the work queue. It will always be greater than or equal to |
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* zero. Therefore a delay of zero will always execute immediately. |
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*/ |
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elapsed = clock_systimer() - work->qtime; |
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if (elapsed >= work->delay) |
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{ |
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/* Remove the ready-to-execute work from the list */ |
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(void)dq_rem((struct dq_entry_s *)work, &g_work); |
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/* Extract the work description from the entry (in case the work |
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* instance by the re-used after it has been de-queued). |
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*/ |
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worker = work->worker; |
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arg = work->arg; |
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/* Mark the work as no longer being queued */ |
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work->worker = NULL; |
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/* Do the work. Re-enable interrupts while the work is being |
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* performed... we don't have any idea how long that will take! |
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*/ |
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irqrestore(flags); |
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worker(arg); |
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/* Now, unfortunately, since we re-enabled interrupts we don't |
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* know the state of the work list and we will have to start |
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* back at the head of the list. |
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*/ |
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flags = irqsave(); |
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work = (FAR struct work_s *)g_work.head; |
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} |
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else |
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{ |
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/* This one is not ready.. will it be ready before the next |
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* scheduled wakeup interval? |
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*/ |
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remaining = elapsed - work->delay; |
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if (remaining < next) |
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{ |
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/* Yes.. Then schedule to wake up when the work is ready */ |
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next = remaining; |
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} |
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/* Then try the next in the list. */ |
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work = (FAR struct work_s *)work->dq.flink; |
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} |
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} |
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/* Now calculate the microsecond delay we should wait */ |
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usec = next * USEC_PER_TICK; |
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} |
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return OK; /* To keep some compilers happy */ |
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} |
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#endif /* CONFIG_SCHED_WORKQUEUE */
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