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Date: Thu, 16 Oct 2008 16:08:13 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Mike Travis <travis@sgi.com>
Cc: laijs@cn.fujitsu.com, adobriyan@gmail.com, menage@google.com, pj@sgi.com,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] seq_file: Add seq_cpumask_list(),
 seq_nodemask_list()
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On Thu, 16 Oct 2008 15:56:30 -0700
Mike Travis <travis@sgi.com> wrote:

> Andrew Morton wrote:
> > On Sun, 12 Oct 2008 17:29:25 +0800
> > Lai Jiangshan <laijs@cn.fujitsu.com> wrote:
> > 
> >> +static inline int seq_cpumask_list(struct seq_file *m, cpumask_t *mask)
> >> +{
> >> +	return seq_bitmap_list(m, mask->bits, NR_CPUS);
> >> +}
> > 
> > Is it possible to avoid using NR_CPUS?  In some situations it'd be much
> > more efficient to use the runtime-determined max possible cpu index.
> > 
> > But I don't immediately recall how to get at that number. 
> > num_possible_cpus() assumes that there are no holes in the CPU
> > identifier list.
> > 
> 
> nr_cpu_ids represents the max index +1 of the possible cpus.  (Usually the
> same as num_possible_cpus() except a.) it doesn't need to do the cpus_weight()
> op, and b.) *if* (a big if) the cpu indices are sparse, then they wouldn't
> be the same values.)

OK, thanks.  I was foggily looking for max_possible_cpus(), to match
num_online_cpus(), num_possible_cpus(), num_present_cpus().  Silly me.