On Mon, Nov 26, 2018 at 04:53:54PM +0100, Frederic Weisbecker wrote: > > > + irq_work_queue_on(&per_cpu(vtime_set_nice_work, cpu), cpu); > > > > What happens if you already had one pending? Do we loose updates? > > No, if irq_work is already pending, it doesn't requeue iff the work hasn't > been executed yet and it's guaranteed it will see the freshest update. > (you should trust more the code you wrote ;-)
Yeah, I do remember hoq irq_work works. What I was asking was about how this specific handler deals with 'missing' updates. Suppose we start with state A, set it to B and raise the IPI, then set it to C before the interrupt happens. That means the irq_work handler will see C and never observe B.
