Messages in this thread | | | Date | Sun, 3 Jan 2016 08:58:39 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH v4 2/2] virtio_balloon: Use a workqueue instead of "vballoon" kthread |
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Hello, Michael.
On Sat, Jan 02, 2016 at 11:36:03PM +0200, Michael S. Tsirkin wrote: > > 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. > > I always thought the right way to defer executing a work queue item > is to queue delayed work, not sleep + queue work.
That works too and is preferable if there are gonna be a lot of work items sleeping but it isn't different from any other blocking.
> Doing a sleep ties up one thread for 1/5 of a second, does it not?
It does.
> If so, as long as it's the only driver doing this, we'll be fine, > but if many others copy this pattern, things will > start to break, will they not?
The maximum concurrency on the system_wq is 256 which is pretty high, so for most use cases, it's fine. If high concurrency is expected, it's better to break it out to a separate workqueue.
Thanks.
-- tejun
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