On Tue, Jan 05, 2016 at 03:49:18PM +0100, Petr Mladek wrote: > On Sat 2016-01-02 23:36:03, Michael S. Tsirkin wrote: > > On Sat, Jan 02, 2016 at 06:43:16AM -0500, Tejun Heo wrote: > > > 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 > > > > > @@ -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. > > > > I didn't realise this. Thanks! > > > > Unfortunately in this case, there can be further requeueing > > if a stats request arrives. > > Please, is there any point where the stat requests are disabled for > sure? I am not 100% sure but it might be after the reset() call: > > vb->vdev->config->reset(vb->vdev);
Yes. > Then we could split the kthread into two works: resizing and stats. > The resizing work still must be canceled before leaking the balloon. > But the stats work might be canceled after the reset() call. > > In fact, the solution with the two works looks even cleaner. > > > Thanks for feedback, > Petr I agree - in fact, not blocking stats call while inflate is blocked would be very nice. As things then happen in parallel, we need to be careful with locking and stuff. That would be a good reason to switch to wq. -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
