Messages in this thread | | | From | Jason Andryuk <> | Date | Thu, 20 May 2021 08:39:56 -0400 | Subject | Calling queue_work() multiple times with the same work_struct |
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Hi,
I'm looking for clarification of the behavior of queue_work(). From the header description, I'm not sure if I need additional complexity for re-queuing work.
I want to ensure the following cases all occur when calling queue_work(). 1) work_struct not queued -> work_struct queued 2) work_struct queued -> work_struct queued (no change) 3) work_struct running -> work_struct queued (so it will run again)
1 & 2 look supported from workqueue.h. Is the 3rd case true and guaranteed? Is it okay to re-use the same work_struct in that case while it's being executed? A work_struct function can re-queue itself, so I hope #3 is supported.
The virtual device I'm working on has a single interrupt shared for multiple rings. So whenever an interrupt occurs, I need to re-queue the single work_struct on the workqueue to ensure we don't miss an event. That is, we need to re-iterate all the rings if the interrupt comes halfway through processing the list of rings. If multiple interrupts come through while running, we only need to re-queue a single work item for all of them.
Below is what I hope works for the code to give something tangible.
Thank you, Jason
DECLARE_WORK(argo_work, argo_work_fn); static struct workqueue_struct *argo_wq = alloc_workqueue("argo_wq", WQ_UNBOUND | WQ_HIGHPRI | WQ_CPU_INTENSIVE | WQ_SYSFS, 1);
static void argo_work_fn(struct work_struct *work) { argo_interrupt_rx(); /* iterates multiple "rings" */ argo_notify(); }
static irqreturn_t argo_interrupt(int irq, void *dev_id) { queue_work(argo_wq, &argo_work);
return IRQ_HANDLED; }
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