Messages in this thread | | | Date | Thu, 20 Nov 2014 18:55:30 +0200 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v3] virtio_balloon: Convert "vballoon" kthread into a workqueue |
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On Thu, Nov 20, 2014 at 11:49:33AM -0500, Tejun Heo wrote: > On Thu, Nov 20, 2014 at 06:47:11PM +0200, Michael S. Tsirkin wrote: > > > There's cancel_work_sync() to stop the self-requeueing ones. > > > > What happens if queue_work runs while cancel_work_sync is in progress? > > Does it fail to queue? > > cancel_work_sync() is guaranteed to take self-requeueing work items no > matter when it's called or what's going on. External (non-self) > queueings of course should be stopped in other ways.
Excellent, thanks a lot.
> > > > From that POV a dedicated WQ kept it simple. > > > > > > A dedicated wq doesn't do anything for that. You can't shut down a > > > workqueue with a pending work item on it. destroy_workqueue() will > > > try to drain the target wq, warn if it doesn't finish in certain > > > number of iterations and just keep trying indefinitely. > > > > > > Thanks. > > > > Right, so eventually we'll stop requeueuing and it will succeed? > > Yeah, sure, it's a silly reason to use a separate workqueue tho. > Don't do it that way. > > Thanks.
Since there's cancel_work_sync I agree.
> -- > tejun
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