Re: [PATCH] net: Adjust softirq raising in __napi_schedule

Johannes Berg
2009-10-26T07:58:56Z

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On Mon, 2009-10-26 at 07:54 +0000, Jarek Poplawski wrote:

> > No, I wrote that I didn't know. I suppose now that I looked at it I do
> > know, and only disabling preemption is required.
>
> But netif_rx has preemption disabled most of the time (by hardirqs
> disabling). So maybe disabling preemption isn't the main reason here
> either?

Not for netpoll though, which may or may not be relevant (if I were to
venture a guess I'd say it isn't and it disables preemption to be able
to do the softirq thing)

However, I lost track now of why we're discussing this.

Basically it boils down to using netif_rx() when in (soft)irq, and
netif_rx_ni() when in process context. That could just be an
optimisation, but it's a very valid one.

johannes

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