Re: [PATCH] percpu-refcount: relax limit on percpu_ref_reinit()

jianchao.wang
2018-09-11T09:38:15Z

Hi Ming

On 09/11/2018 12:03 PM, Ming Lei wrote:
> After the refcount is switched to atomic mode, the whole counting is
> done on the atomic part. Then if the refcount need to switch to percpu mode
> again, all percpu part of the counter is re-initialized as zero simply. This
> is invariant with/without this patch.

Does the "whole counting" here means ?

(long)(sum (every cpu's refcounter)) + atomic refcounter

and when switch to atomic mode, there could be value left in atomic refcounter.
then the unsigned long percpu refcounter cound be decreased from 0.

>From another angle, one request could be ended on a different cpu from the one where
it is issued.

Thanks
Jianchao