Re: [Xen-devel] [PATCH net-next] xen-netback: Schedule NAPI from dealloc thread instead of callback

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Thu, 2014-03-13 at 10:17 +0000, Wei Liu wrote:
> On Wed, Mar 12, 2014 at 09:04:41PM +0000, Zoltan Kiss wrote:
> > If there are unconsumed requests in the ring, but there isn't enough free
> > pending slots, the NAPI instance deschedule itself. As the frontend won't 
> > send
> > any more interrupts in this case, it is the task of whoever release the 
> > pending
> > slots to schedule the NAPI instance in this case. Originally it was done in 
> > the
> > callback, but it's better at the end of the dealloc thread, otherwise there 
> > is
> > a risk that the NAPI instance just deschedule itself as the dealloc thread
> > couldn't release any used slot yet. However, as there are a lot of pending
> > packets, NAPI will be scheduled again, and it is very unlikely that the 
> > dealloc
> > thread can't release enough slots in the meantime.
> > 
> 
> So this patch restores the property that "only two parties access the
> ring", right?

I think so, and therefore:
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>

Ian.



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