From: Jason Andryuk <jandryuk@gmail.com>
To: Tejun Heo <tj@kernel.org>, Lai Jiangshan <jiangshanlai@gmail.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Calling queue_work() multiple times with the same work_struct
Date: Thu, 20 May 2021 08:39:56 -0400 [thread overview]
Message-ID: <CAKf6xptjmd9BMuiKpRgj1YyyR97gGXKgYgj-4CKaTvBk4+FeoA@mail.gmail.com> (raw)
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;
}
next reply other threads:[~2021-05-20 13:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-20 12:39 Jason Andryuk [this message]
2021-05-20 17:01 ` Calling queue_work() multiple times with the same work_struct Tejun Heo
2021-05-20 17:31 ` Jason Andryuk
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