RE: [EXT] Re: [PATCH RFC net-next 11/19] net: mvpp2: add flow control RXQ and BM pool config callbacks

[Stefan Chulski]

> >
> > +/* Routine calculate single queue shares address space */ static int
> > +mvpp22_calc_shared_addr_space(struct mvpp2_port *port) {
> > +	/* If number of CPU's greater than number of threads, return last
> > +	 * address space
> > +	 */
> > +	if (num_active_cpus() >= MVPP2_MAX_THREADS)
> > +		return MVPP2_MAX_THREADS - 1;
> > +
> > +	return num_active_cpus();
> 
> Firstly - this can be written as:
> 
> 	return min(num_active_cpus(), MVPP2_MAX_THREADS - 1);

OK.

> Secondly - what if the number of active CPUs change, for example due to
> hotplug activity. What if we boot with maxcpus=1 and then bring the other
> CPUs online after networking has been started? The number of active CPUs is
> dynamically managed via the scheduler as CPUs are brought online or offline.
> 
> > +/* Routine enable flow control for RXQs conditon */ void
> > +mvpp2_rxq_enable_fc(struct mvpp2_port *port)
> ...
> > +/* Routine disable flow control for RXQs conditon */ void
> > +mvpp2_rxq_disable_fc(struct mvpp2_port *port)
> 
> Nothing seems to call these in this patch, so on its own, it's not obvious how
> these are being called, and therefore what remedy to suggest for
> num_active_cpus().

I don't think that current driver support CPU hotplug, anyway I can remove  num_active_cpus
and just use shared RX IRQ ID.

Thanks.
.