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Diffstat (limited to 'nuttx/sched/work_thread.c')
| -rw-r--r-- | nuttx/sched/work_thread.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/nuttx/sched/work_thread.c b/nuttx/sched/work_thread.c new file mode 100644 index 000000000..fe14ae5e5 --- /dev/null +++ b/nuttx/sched/work_thread.c @@ -0,0 +1,215 @@ +/**************************************************************************** + * sched/work_thread.c + * + * Copyright (C) 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 <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 = clock_systimer() - 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 */ |