On Sat, 28 Jun 2008, Leon Woestenberg wrote:
>
> Against 2.6.25.8-rt7, only compile tested.
>
> Adds schedule_work_prio() and queue_work_prio() so that work can be
> scheduled with a different priority than the caller.
>
> Under PREEMPT RT, schedule_work() and therefore queue_work() makes
> the work inherit the caller's priority.
>
> If a real-time thread, such as an interrupt handler, defers work it
> may want the deferred work to be of lower priority so it does not
> race with succeeding interrupt handling.
>
> Signed-off-by: Leon Woestenberg <leon@xxxxxxxxxxxxxx>
>
> Index: linux-2.6.25.8/kernel/workqueue.c
> ===================================================================
> --- linux-2.6.25.8.orig/kernel/workqueue.c 2008-06-28 16:52:40.000000000 +0200
> +++ linux-2.6.25.8/kernel/workqueue.c 2008-06-28 18:29:19.000000000 +0200
> @@ -162,9 +162,10 @@
> }
>
> /**
> - * queue_work - queue work on a workqueue
> + * queue_work_prio - queue work on a workqueue and set work priority
> * @wq: workqueue to use
> * @work: work to queue
> + * @prio: priority of work
> *
> * Returns 0 if @work was already on a queue, non-zero otherwise.
> *
> @@ -173,7 +174,7 @@
> *
> * Especially no such guarantee on PREEMPT_RT.
> */
> -int queue_work(struct workqueue_struct *wq, struct work_struct *work)
> +int queue_work_prio(struct workqueue_struct *wq, struct work_struct
> *work, int prio)
> {
> int ret = 0, cpu = raw_smp_processor_id();
>
> @@ -184,6 +185,25 @@
> }
> return ret;
> }
> +EXPORT_SYMBOL_GPL(queue_work_prio);
This function doesn't look like it does anything with the new "prio"
field.
-- Steve
> +
> +/**
> + * queue_work - queue work on a workqueue. work inherits caller's prio.
> + * @wq: workqueue to use
> + * @work: work to queue
> + *
> + * Returns 0 if @work was already on a queue, non-zero otherwise.
> + *
> + * We queue the work to the CPU it was submitted, but there is no
> + * guarantee that it will be processed by that CPU.
> + *
> + * Especially no such guarantee on PREEMPT_RT.
> + */
> +int queue_work(struct workqueue_struct *wq, struct work_struct *work)
> +{
> + return queue_work(struct workqueue_struct *wq, struct work_struct *work,
> + current->normal_prio);
> +}
> EXPORT_SYMBOL_GPL(queue_work);
>
> static void delayed_work_timer_fn(unsigned long __data)
> @@ -626,7 +646,8 @@
> * schedule_work - put work task in global workqueue
> * @work: job to be done
> *
> - * This puts a job in the kernel-global workqueue.
> + * This puts a job in the kernel-global workqueue. The job inherits the
> + * caller's priority.
> */
> int schedule_work(struct work_struct *work)
> {
> @@ -635,6 +656,19 @@
> EXPORT_SYMBOL(schedule_work);
>
> /**
> + * schedule_work_prio - put work task in global workqueue, set work prio
> + * @work: job to be done
> + *
> + * This puts a job in the kernel-global workqueue. The job gets the specified
> + * priority.
> + */
> +int schedule_work_prio(struct work_struct *work, int prio)
> +{
> + return queue_work_prio(keventd_wq, work, prio);
> +}
> +EXPORT_SYMBOL(schedule_work_prio);
> +
> +/**
> * schedule_delayed_work - put work task in global workqueue after delay
> * @dwork: job to be done
> * @delay: number of jiffies to wait or 0 for immediate execution
>
> --
> Leon
> --
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