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User-mode work queue logic should not disable interrupts

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This commit is contained in:
Gregory Nutt
2014-10-10 14:52:04 -06:00
parent 16a3e83258
commit cf59a195ba
14 changed files with 654 additions and 101 deletions
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sched/wqueue/Make.defs
+1 -1
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@@ -37,7 +37,7 @@
ifeq ($(CONFIG_SCHED_WORKQUEUE),y)
CSRCS += kwork_queue.c kwork_cancel.c kwork_signal.c
CSRCS += kwork_queue.c kwork_process.c kwork_cancel.c kwork_signal.c
# Add high priority work queue files
sched/wqueue/kwork_cancel.c
+57
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@@ -39,8 +39,11 @@
#include <nuttx/config.h>
#include <queue.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/arch.h>
#include <nuttx/wqueue.h>
#include "wqueue/wqueue.h"
@@ -67,6 +70,60 @@
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: work_qcancel
*
* Description:
* Cancel previously queued work. This removes work from the work queue.
* After work has been cancelled, it may be re-queue by calling work_queue()
* again.
*
* Input parameters:
* qid - The work queue ID
* work - The previously queue work structure to cancel
*
* Returned Value:
* Zero (OK) on success, a negated errno on failure. This error may be
* reported:
*
* -ENOENT - There is no such work queued.
* -EINVAL - An invalid work queue was specified
*
****************************************************************************/
static int work_qcancel(FAR struct wqueue_s *wqueue, FAR struct work_s *work)
{
irqstate_t flags;
int ret = -ENOENT;
DEBUGASSERT(work != NULL);
/* Cancelling the work is simply a matter of removing the work structure
* from the work queue. This must be done with interrupts disabled because
* new work is typically added to the work queue from interrupt handlers.
*/
flags = irqsave();
if (work->worker != NULL)
{
/* A little test of the integrity of the work queue */
DEBUGASSERT(work->dq.flink || (FAR dq_entry_t *)work == wqueue->q.tail);
DEBUGASSERT(work->dq.blink || (FAR dq_entry_t *)work == wqueue->q.head);
/* Remove the entry from the work queue and make sure that it is
* mark as available (i.e., the worker field is nullified).
*/
dq_rem((FAR dq_entry_t *)work, &wqueue->q);
work->worker = NULL;
ret = OK;
}
irqrestore(flags);
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
sched/wqueue/kwork_process.c
+251
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@@ -0,0 +1,251 @@
/****************************************************************************
* libc/wqueue/work_process.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 <stdint.h>
#include <unistd.h>
#include <queue.h>
#include <nuttx/clock.h>
#include <nuttx/wqueue.h>
#include <arch/irq.h>
#ifdef CONFIG_SCHED_WORKQUEUE
/****************************************************************************
* 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
#ifndef MIN
# define MIN(a,b) ((a) < (b) ? (a) : (b))
#endif
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public 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 wqueue_s *wqueue)
{
volatile FAR struct work_s *work;
worker_t worker;
irqstate_t flags;
FAR void *arg;
uint32_t elapsed;
uint32_t remaining;
uint32_t stick;
uint32_t ctick;
uint32_t next;
/* Then process queued work. We need to keep interrupts disabled while
* we process items in the work list.
*/
next = wqueue->delay;
flags = irqsave();
/* Get the time that we started this polling cycle in clock ticks. */
stick = clock_systimer();
/* And check each entry in the work queue. Since we have disabled
* interrupts 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)
{
DEBUGASSERT(wqueue->wq_sem.count > 0);
/* 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_systimer();
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 re-enabling interrupts) */
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 this 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 *)wqueue->q.head;
}
else
{
/* Cancelled.. Just move to the next work in the list with
* interrupts still disabled.
*/
work = (FAR struct work_s *)work->dq.flink;
}
}
else
{
/* This one is not ready.. will it be ready before the next
* scheduled wakeup interval?
*
* NOTE that elapsed is relative to the the current time,
* not the time of beginning of this queue processing pass.
* So it may need an adjustment.
*/
elapsed += (ctick - stick);
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;
}
}
/* Get the delay (in clock ticks) since we started the sampling */
elapsed = clock_systimer() - work->qtime;
if (elapsed <= wqueue->delay)
{
/* How must time would we need to delay to get to the end of the
* sampling period? The amount of time we delay should be the smaller
* of the time to the end of the sampling period and the time to the
* next work expiry.
*/
remaining = wqueue->delay - elapsed;
next = MIN(next, remaining);
if (next > 0)
{
/* 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.
*/
usleep(next * USEC_PER_TICK);
}
}
irqrestore(flags);
}
#endif /* CONFIG_SCHED_WORKQUEUE */
sched/wqueue/kwork_queue.c
+61
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@@ -40,8 +40,12 @@
#include <nuttx/config.h>
#include <stdint.h>
#include <queue.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/arch.h>
#include <nuttx/clock.h>
#include <nuttx/wqueue.h>
#include "wqueue/wqueue.h"
@@ -68,6 +72,63 @@
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: work_qqueue
*
* Description:
* Queue work to be performed at a later time. All queued work will be
* performed on the worker thread of of execution (not the caller's).
*
* The work structure is allocated by caller, but completely managed by
* the work queue logic. The caller should never modify the contents of
* the work queue structure; the caller should not call work_queue()
* again until either (1) the previous work has been performed and removed
* from the queue, or (2) work_cancel() has been called to cancel the work
* and remove it from the work queue.
*
* Input parameters:
* qid - The work queue ID (index)
* work - The work structure to queue
* worker - The worker callback to be invoked. The callback will invoked
* on the worker thread of execution.
* arg - The argument that will be passed to the workder callback when
* int is invoked.
* delay - Delay (in clock ticks) from the time queue until the worker
* is invoked. Zero means to perform the work immediately.
*
* Returned Value:
* Zero on success, a negated errno on failure
*
****************************************************************************/
static int work_qqueue(FAR struct wqueue_s *wqueue, FAR struct work_s *work,
worker_t worker, FAR void *arg, uint32_t delay)
{
irqstate_t flags;
DEBUGASSERT(work != NULL);
/* First, initialize the work structure */
work->worker = worker; /* Work callback */
work->arg = arg; /* Callback argument */
work->delay = delay; /* Delay until work performed */
/* Now, time-tag that entry and put it in the work queue. This must be
* done with interrupts disabled. This permits this function to be called
* from with task logic or interrupt handlers.
*/
flags = irqsave();
work->qtime = clock_systimer(); /* Time work queued */
dq_addlast((FAR dq_entry_t *)work, &wqueue->q);
kill(wqueue->pid[0], SIGWORK); /* Wake up the worker thread */
irqrestore(flags);
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
sched/wqueue/wqueue.h
+19
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@@ -123,5 +123,24 @@ int work_hpstart(void);
int work_lpstart(void);
#endif
/****************************************************************************
* 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 wqueue_s *wqueue);
#endif /* CONFIG_SCHED_WORKQUEUE */
#endif /* __SCHED_WQUEUE_WQUEUE_H */