Hello, Michael.

On Tue, Dec 20, 2011 at 09:09:08PM +0200, Michael S. Tsirkin wrote:

Another question, wanted to make sure:
virtnet_poll does schedule_delayed_work(&vi->refill, 0);
separately refill work itself also does
schedule_delayed_work(&vi->refill, HZ/2);
If two such events happen twice, on different CPUs, we are still guaranteed
the work will only run once, right?

No, it's not.  Normal workqueues only guarantee non-reentrance on
local CPU.  If you want to guarantee that only one instance of a given
item is executing across all CPUs, you need to use the nrt workqueue.

Thanks.

-- 
tejun