Re: [PATCH] lib/cpumask.c: Optimize __any_online_cpu() calculation

From: Rusty Russell
Date: Wed Feb 15 2012 - 20:52:23 EST


On Wed, 15 Feb 2012 19:49:00 +0530, "Srivatsa S. Bhat" <srivatsa.bhat@xxxxxxxxxxxxxxxxxx> wrote:
> On 02/15/2012 06:27 PM, Eric Dumazet wrote:
>
> > Le mercredi 15 fÃvrier 2012 Ã 18:05 +0530, Srivatsa S. Bhat a Ãcrit :
> >> __any_online_cpu() uses a for loop at the moment.
> >> Instead, use cpumask_* operations to speed it up.
> >>
> >> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
> >> ---
> >> Actually, the patch posted at https://lkml.org/lkml/2012/2/15/101 removed
> >> the last user of any_online_cpu() (and hence __any_online_cpu()).
> >> However, since this is an exported symbol, I refrained from removing this
> >> function altogether.
> >
> > Just remove the export/function and eventually leave the helper ?
> >
> > #define any_online_cpu(mask) cpumask_any_and(mask, cpu_online_mask)
> >
>
>
> That sounds good. Here is v2 of the patch.
> (Since this v2 touches include/linux/cpumask.h, I rebased it on top of the
> patch posted at: https://lkml.org/lkml/2012/2/15/2. Even without that
> patch it should apply with minor line number changes..)

No. Just git rid of the only caller of any_online_cpu():

arch/ia64/kernel/smpboot.c:693: new_cpei_cpu = any_online_cpu(cpu_online_map);

Thanks,
Rusty.
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