Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit architectures

Tejun Heo
2016-04-08T17:46:34Z

Hello,

On Fri, Apr 08, 2016 at 01:32:52PM -0400, Waiman Long wrote:
> Yes, I think it will be more efficient to use percpu_counter in this case.
> The preempt_disable/enable() calls are pretty cheap. Once in a while, you
> need to take the lock and update the global count. How about I change the
> 2nd patch to use percpu_counter internally when 64-bit counts are needed in
> 32-bit archs, but use the regular percpu counts on 64-bit archs? If you are
> OK with that, I can update the patch accordingly.

Does having percpu_stats as a separate construct make sense after
that? Just use percpu_counter directly? You end up wasting a bit
more space that way but most of space overhead for these things are in
percpu part anyway, so in proportion it shouldn't make that much of a
difference.

Thanks.

--
tejun