Re: mm: Do not iterate over NR_CPUS in __zone_pcp_update()

From: Robert P. J. Day
Date: Tue Mar 09 2010 - 16:04:21 EST


On Tue, 9 Mar 2010, Christoph Lameter wrote:

> On Tue, 9 Mar 2010, Robert P. J. Day wrote:
>
> > > I'm having trouble working out whether we want to backport this into
> > > 2.6.33.x or earlier. Help?
> >
> > given the above aesthetic mod, shouldn't that same change be
> > applied to *all* explicit loops of that form? after all,
> > checkpatch.pl warns against it:
>
> The number of NR_CPUS should be significantly less after the percpu
> rework. Would you audit the kernel for NR_CPUS use?

i just did a simple grep for the obvious pattern:

$ grep -r "for.*NR_CPUS" *
arch/sparc/mm/init_64.c: for (i = 0; i < NR_CPUS; i++)
arch/sparc/kernel/sun4d_smp.c: for (i = 0; i < NR_CPUS; i++) {
arch/sparc/kernel/traps_64.c: for (i = 0; i < NR_CPUS; i++) {
... etc etc ...

most of the occurrences are under arch/. as you say, after the
rework, most of those should be replaceable.

rday
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Robert P. J. Day Waterloo, Ontario, CANADA

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