Re: [PATCH 1/3] cpumask: add for_each_online_cpu_mask_nr function

From: Mike Travis
Date: Fri Sep 12 2008 - 10:17:21 EST

Rusty Russell wrote:
> On Wednesday 10 September 2008 01:50:14 Mike Travis wrote:
>> * Add for_each_online_cpu_mask_nr() function to eliminate need for
>> a common use of a temporary cpumask_t variable. When the following
>> procedure is being used:
>> funcproto(cpumask_t *mask, ...)
>> {
>> cpumask_t temp;
>> cpus_and(temp, *mask, cpu_online_map);
>> for_each_cpu_mask_nr(cpu, temp)
>> ...
>> If then becomes:
>> funcproto(cpumask_t *mask, ...)
>> {
>> for_each_online_cpu_mask_nr(cpu, *mask)
>> ...
>> * Note the generic __next_cpu_and (and __next_cpu_and_nr) functions
>> allowing AND'ing with any cpumask_t variable, not just the
>> cpu_online_map.
> Good idea! But I really dislike the _nr versions (too many names!). Do we
> really need them, since by definition cpus after nr_cpu_ids are never
> online...
> (And we should initialize nr_cpu_ids to NR_CPUS so even early boot works, if
> we don't already...).
> Cheers,
> Rusty.

Yes, the only reason the _nr is there is to be consistent with the
current for_each_cpu_mask{,_nr} functions. What I'd like to do is
convert all calls to use the nr_cpu_ids and if there's some reason
to need to iterate over NR_CPUS range, then you'd use FOR_EACH_CPU_MASK.

And yes, nr_cpu_ids is init'd to NR_CPUS.

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