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. -- tejun
