Messages in this thread | | | Date | Thu, 24 Sep 2020 10:57:58 -0400 | From | Tejun Heo <> | Subject | Re: sched: rq->nr_iowait transiently going negative after the recent p->on_cpu optimization |
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On Thu, Sep 24, 2020 at 04:50:41PM +0200, Peter Zijlstra wrote: > > Rik suggested that it'd be sufficient to return 0 on underflow especially > > given that 0 is actually the right number to describe the state. So, maybe > > that can be a nicer code-wise? > > I worry about things where one CPU has a positive value and one or more > (other) CPUs have a temporary negative value.
I think it'd make more sense to max'ing them per-cpu as that's the right per-cpu state. nr_iowait_cpu() needs that anyway, so maybe the summing function can just use nr_iowait_cpu()?
Thanks.
-- tejun
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