Messages in this thread | | | Date | Sat, 2 Jan 2016 06:43:16 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH v4 2/2] virtio_balloon: Use a workqueue instead of "vballoon" kthread |
| |
Hello,
On Fri, Jan 01, 2016 at 12:18:17PM +0200, Michael S. Tsirkin wrote: > > My initial idea was to use a dedicated workqueue. Michael S. Tsirkin > > suggested using a system one. Tejun Heo confirmed that the system > > workqueue has a pretty high concurrency level (256) by default. > > Therefore we need not be afraid of too long blocking. > > Right but fill has a 1/5 second sleep on failure - *that* > is problematic for a system queue.
Why so? As long as the maximum concurrently used workers are not high, 1/5 second or even a lot longer sleeps are completely fine.
> > @@ -563,7 +534,7 @@ static void virtballoon_remove(struct virtio_device *vdev) > > struct virtio_balloon *vb = vdev->priv; > > > > unregister_oom_notifier(&vb->nb); > > - kthread_stop(vb->thread); > > + cancel_work_sync(&vb->wq_work); > > OK but since job requeues itself, cancelling like this might not be enough.
As long as there's no further external queueing, cancel_work_sync() is guaranteed to kill a self-requeueing work item.
Thanks.
-- tejun
| |