Messages in this thread | | | Date | Tue, 7 Jul 2020 11:47:18 +0200 | From | Peter Zijlstra <> | Subject | Re: weird loadavg on idle machine post 5.7 |
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On Tue, Jul 07, 2020 at 10:20:05AM +0100, Qais Yousef wrote: > On 07/06/20 16:59, Peter Zijlstra wrote:
> > + if (!preempt && prev_state && prev_state == prev->state) { > > I think the compiler won't optimize `prev_state == prev->state` out because of > the smp_mb__after_spinlock() which implies a compiler barrier. Still not sure > if it's worth making prev->state accesses a READ_ONCE()?
task_struct::state is one of the very rare (and ancient) variables that's declared volatile.
We should probably clean that up some day, but so far I've not attempted to do such a thing.
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