Messages in this thread | | | Subject | Re: Optimisation for smp_num_cpus loop in hotplug | Date | Fri, 21 Jun 2002 11:31:44 -0400 | From | James Bottomley <> |
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rusty@rustcorp.com.au said: > Yeah, it's simple, and none of the current ones are really critical. > But I think we're better off with: > for (i = first_cpu(); i < NR_CPUS; i = next_cpu(i)) {
> Which is simple enough not to need an iterator macro, and also has the > bonus of giving irq-balancing et al. an efficient, portable way of > looking for the "next" cpu.
So you're thinking that next_cpu(i) is something like
__ffs((~(unsigned)((1<<i)-1) & cpu_online_map)
plus an extra exception piece to take next_cpu(i) above NR_CPUS if we have no remaining CPUs (because __ffs would be undefined)? It's the exception piece that I don't see how to do really efficiently.
James
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