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Subject: Re: [PATCH] percpu-refcount: relax limit on percpu_ref_reinit()
To: Tejun Heo <tj@kernel.org>
Cc: Ming Lei <ming.lei@redhat.com>, linux-kernel@vger.kernel.org,
        Kent Overstreet <kent.overstreet@gmail.com>,
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From: "jianchao.wang" <jianchao.w.wang@oracle.com>
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Date: Tue, 11 Sep 2018 22:13:23 +0800
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Hi tejun

On 09/11/2018 09:44 PM, Tejun Heo wrote:
> Hello,
> 
> On Tue, Sep 11, 2018 at 12:40:36PM +0800, jianchao.wang wrote:
>> (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.
> 
> It can always do that.  Imagine a task getting a ref on one cpu,
> migrating and putting it on another.  The only thing which matters is
> that the sum of everything adds upto what it should be.
> 

Thanks for your kindly response.
I have got the point here.

Thanks
Jianchao